CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Help:Conditional expressions - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"b83128a9-2e59-4100-85f4-765daacb3a51","wgCanonicalNamespace":"Help","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":12,"wgPageName":"Help:Conditional_expressions","wgTitle":"Conditional expressions","wgCurRevisionId":1256674841,"wgRevisionId":1256674841,"wgArticleId":39526065,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["ParserFunction errors","Wikipedia how-to","MediaWiki Help","Wikipedia template help"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Help:Conditional_expressions","wgRelevantArticleId":39526065,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false, "wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":30000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgDiscussionToolsFeaturesEnabled":{"replytool":true,"newtopictool":true,"sourcemodetoolbar":true,"topicsubscription":false,"autotopicsub":false,"visualenhancements":false,"visualenhancements_reply":false,"visualenhancements_pageframe":false},"wgDiscussionToolsFallbackEditMode":"source","wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q8614470","wgCheckUserClientHintsHeadersJsApi":[ "brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.pygments":"ready","ext.discussionTools.init.styles":"ready","oojs-ui-core.styles":"ready","oojs-ui.styles.indicators":"ready","mediawiki.widgets.styles":"ready","oojs-ui-core.icons":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.pygments.view", "site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.discussionTools.init","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","wikibase.client.vector-2022","ext.checkUser.clientHints","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.discussionTools.init.styles%7Cext.pygments%2CwikimediaBadges%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cmediawiki.widgets.styles%7Coojs-ui-core.icons%2Cstyles%7Coojs-ui.styles.indicators%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Help:Conditional expressions - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Help:Conditional_expressions"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Help:Conditional_expressions&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Help:Conditional_expressions"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="ext-discussiontools-replytool-enabled ext-discussiontools-newtopictool-enabled ext-discussiontools-sourcemodetoolbar-enabled skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-12 ns-subject mw-editable page-Help_Conditional_expressions rootpage-Help_Conditional_expressions skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Help%3AConditional+expressions" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Help%3AConditional+expressions" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Help%3AConditional+expressions" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Help%3AConditional+expressions" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Summary" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Summary"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Summary</span> </div> </a> <ul id="toc-Summary-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#if" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#if"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Using #if</span> </div> </a> <ul id="toc-Using_#if-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#ifeq" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#ifeq"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Using #ifeq</span> </div> </a> <ul id="toc-Using_#ifeq-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#switch" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#switch"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Using #switch</span> </div> </a> <ul id="toc-Using_#switch-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#expr" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#expr"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Using #expr</span> </div> </a> <ul id="toc-Using_#expr-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#ifexpr" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#ifexpr"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Using #ifexpr</span> </div> </a> <ul id="toc-Using_#ifexpr-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#iferror" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#iferror"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Using #iferror</span> </div> </a> <ul id="toc-Using_#iferror-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Using_#ifexist" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Using_#ifexist"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Using #ifexist</span> </div> </a> <ul id="toc-Using_#ifexist-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Checking_for_template_parameters" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Checking_for_template_parameters"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Checking for template parameters</span> </div> </a> <ul id="toc-Checking_for_template_parameters-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Variadic_templates" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Variadic_templates"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Variadic templates</span> </div> </a> <ul id="toc-Variadic_templates-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-namespace">Help</span><span class="mw-page-title-separator">:</span><span class="mw-page-title-main">Conditional expressions</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 23 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-23" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">23 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Hilfe:Vorlagenprogrammierung" title="Hilfe:Vorlagenprogrammierung – German" lang="de" hreflang="de" data-title="Hilfe:Vorlagenprogrammierung" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-dsb mw-list-item"><a href="https://dsb.wikipedia.org/wiki/Pomoc:P%C5%9Bed%C5%82ogowe_programowanje" title="Pomoc:Pśedłogowe programowanje – Lower Sorbian" lang="dsb" hreflang="dsb" data-title="Pomoc:Pśedłogowe programowanje" data-language-autonym="Dolnoserbski" data-language-local-name="Lower Sorbian" class="interlanguage-link-target"><span>Dolnoserbski</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Aide:Fonctions_parseur" title="Aide:Fonctions parseur – French" lang="fr" hreflang="fr" data-title="Aide:Fonctions parseur" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-inh mw-list-item"><a href="https://inh.wikipedia.org/wiki/%D0%92%D0%B8%D0%BA%D0%B8%D0%BF%D0%B5%D0%B4%D0%B8:%D0%9F%D0%B0%D1%80%D1%81%D0%B5%D1%80%D0%B0_%D1%84%D1%83%D0%BD%D0%BA%D1%86%D0%B5%D1%88" title="Википеди:Парсера функцеш – Ingush" lang="inh" hreflang="inh" data-title="Википеди:Парсера функцеш" data-language-autonym="ГӀалгӀай" data-language-local-name="Ingush" class="interlanguage-link-target"><span>ГӀалгӀай</span></a></li><li class="interlanguage-link interwiki-hsb mw-list-item"><a href="https://hsb.wikipedia.org/wiki/Pomoc:P%C5%99ed%C5%82ohowe_programowanje" title="Pomoc:Předłohowe programowanje – Upper Sorbian" lang="hsb" hreflang="hsb" data-title="Pomoc:Předłohowe programowanje" data-language-autonym="Hornjoserbsce" data-language-local-name="Upper Sorbian" class="interlanguage-link-target"><span>Hornjoserbsce</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Pomo%C4%87:Funkcije_parsera" title="Pomoć:Funkcije parsera – Croatian" lang="hr" hreflang="hr" data-title="Pomoć:Funkcije parsera" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Bantuan:Ungkapan_bersyarat" title="Bantuan:Ungkapan bersyarat – Indonesian" lang="id" hreflang="id" data-title="Bantuan:Ungkapan bersyarat" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Hj%C3%A1lp:%C3%9E%C3%A1ttunar_a%C3%B0ger%C3%B0ir" title="Hjálp:Þáttunar aðgerðir – Icelandic" lang="is" hreflang="is" data-title="Hjálp:Þáttunar aðgerðir" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Aiuto:Funzioni_parser" title="Aiuto:Funzioni parser – Italian" lang="it" hreflang="it" data-title="Aiuto:Funzioni parser" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A2%D7%96%D7%A8%D7%94:%D7%94%D7%95%D7%A8%D7%90%D7%95%D7%AA_%D7%AA%D7%A0%D7%90%D7%99" title="עזרה:הוראות תנאי – Hebrew" lang="he" hreflang="he" data-title="עזרה:הוראות תנאי" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/H%C3%ABllef:Schablouneprogramm%C3%A9ierung" title="Hëllef:Schablouneprogramméierung – Luxembourgish" lang="lb" hreflang="lb" data-title="Hëllef:Schablouneprogramméierung" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Help:Parserfuncties" title="Help:Parserfuncties – Dutch" lang="nl" hreflang="nl" data-title="Help:Parserfuncties" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/Help:%E6%9D%A1%E4%BB%B6%E6%96%87" title="Help:条件文 – Japanese" lang="ja" hreflang="ja" data-title="Help:条件文" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Pomoc:Funkcje_parsera" title="Pomoc:Funkcje parsera – Polish" lang="pl" hreflang="pl" data-title="Pomoc:Funkcje parsera" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Ajuda:Fun%C3%A7%C3%B5es_sint%C3%A1ticas" title="Ajuda:Funções sintáticas – Portuguese" lang="pt" hreflang="pt" data-title="Ajuda:Funções sintáticas" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%92%D0%B8%D0%BA%D0%B8%D0%BF%D0%B5%D0%B4%D0%B8%D1%8F:%D0%A4%D1%83%D0%BD%D0%BA%D1%86%D0%B8%D0%B8_%D0%BF%D0%B0%D1%80%D1%81%D0%B5%D1%80%D0%B0" title="Википедия:Функции парсера – Russian" lang="ru" hreflang="ru" data-title="Википедия:Функции парсера" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Help:Conditional_expressions" title="Help:Conditional expressions – Simple English" lang="en-simple" hreflang="en-simple" data-title="Help:Conditional expressions" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Pomo%C4%8D:ParserFunctions" title="Pomoč:ParserFunctions – Slovenian" lang="sl" hreflang="sl" data-title="Pomoč:ParserFunctions" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%94%D0%BE%D0%B2%D1%96%D0%B4%D0%BA%D0%B0:%D0%A4%D1%83%D0%BD%D0%BA%D1%86%D1%96%D1%97_%D0%BF%D0%B0%D1%80%D1%81%D0%B5%D1%80%D0%B0" title="Довідка:Функції парсера – Ukrainian" lang="uk" hreflang="uk" data-title="Довідка:Функції парсера" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%85%D8%B9%D8%A7%D9%88%D9%86%D8%AA:%D8%B4%D8%B1%D8%B7%DB%8C%DB%81_%D8%AC%D9%85%D9%84%DB%92" title="معاونت:شرطیہ جملے – Urdu" lang="ur" hreflang="ur" data-title="معاونت:شرطیہ جملے" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Tr%E1%BB%A3_gi%C3%BAp:T%C3%ADnh_to%C3%A1n" title="Trợ giúp:Tính toán – Vietnamese" lang="vi" hreflang="vi" data-title="Trợ giúp:Tính toán" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/%D7%B0%D7%99%D7%A7%D7%99%D7%A4%D6%BC%D7%A2%D7%93%D7%99%D7%A2:%D7%A4%D7%90%D7%A8%D7%96%D7%A2%D7%A8_%D7%A4%D7%95%D7%A0%D7%A7%D7%A6%D7%99%D7%90%D7%A0%D7%A2%D7%9F" title="װיקיפּעדיע:פארזער פונקציאנען – Yiddish" lang="yi" hreflang="yi" data-title="װיקיפּעדיע:פארזער פונקציאנען" data-language-autonym="ייִדיש" data-language-local-name="Yiddish" class="interlanguage-link-target"><span>ייִדיש</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/Help:%E8%A7%A3%E6%9E%90%E5%99%A8%E5%87%BD%E6%95%B0" title="Help:解析器函数 – Chinese" lang="zh" hreflang="zh" data-title="Help:解析器函数" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q8614470#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-help" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Help:Conditional_expressions" title="View the help page [c]" accesskey="c"><span>Help page</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Help_talk:Conditional_expressions" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Help:Conditional_expressions"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Help:Conditional_expressions"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Help:Conditional_expressions" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Help:Conditional_expressions" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&oldid=1256674841" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHelp%3AConditional_expressions"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHelp%3AConditional_expressions"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Help%3AConditional_expressions&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Help:Conditional_expressions&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-mediawiki mw-list-item"><a href="https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions" hreflang="en"><span>MediaWiki</span></a></li><li class="wb-otherproject-link wb-otherproject-meta mw-list-item"><a href="https://meta.wikimedia.org/wiki/Help:Parser_function" hreflang="en"><span>Meta-Wiki</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q8614470" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For more detailed instructions, see <a href="https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions" class="extiw" title="mw:Help:Extension:ParserFunctions">mw:Help:Extension:ParserFunctions</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1238436933">.mw-parser-output .ombox{margin:4px 0;border-collapse:collapse;border:1px solid #a2a9b1;background-color:var(--background-color-neutral-subtle,#f8f9fa);box-sizing:border-box;color:var(--color-base,#202122)}.mw-parser-output .ombox.mbox-small{font-size:88%;line-height:1.25em}.mw-parser-output .ombox-speedy{border:2px solid #b32424;background-color:#fee7e6}.mw-parser-output .ombox-delete{border:2px solid #b32424}.mw-parser-output .ombox-content{border:1px solid #f28500}.mw-parser-output .ombox-style{border:1px solid #fc3}.mw-parser-output .ombox-move{border:1px solid #9932cc}.mw-parser-output .ombox-protection{border:2px solid #a2a9b1}.mw-parser-output .ombox .mbox-text{border:none;padding:0.25em 0.9em;width:100%}.mw-parser-output .ombox .mbox-image{border:none;padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .ombox .mbox-imageright{border:none;padding:2px 0.9em 2px 0;text-align:center}.mw-parser-output .ombox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ombox .mbox-invalid-type{text-align:center}@media(min-width:720px){.mw-parser-output .ombox{margin:4px 10%}.mw-parser-output .ombox.mbox-small{clear:right;float:right;margin:4px 0 4px 1em;width:238px}}body.skin--responsive .mw-parser-output table.ombox img{max-width:none!important}@media screen{html.skin-theme-clientpref-night .mw-parser-output .ombox-speedy{background-color:#310402}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .ombox-speedy{background-color:#310402}}</style><table class="plainlinks ombox ombox-notice" role="presentation"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Twemoji_1f527.svg/30px-Twemoji_1f527.svg.png" decoding="async" width="30" height="30" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Twemoji_1f527.svg/45px-Twemoji_1f527.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Twemoji_1f527.svg/60px-Twemoji_1f527.svg.png 2x" data-file-width="512" data-file-height="512"/></span></span></td><td class="mbox-text"><div style="padding-top: 6px; padding-bottom: 5px;"><b>This help page is a <a href="/wiki/Wikipedia:Project_namespace#Wikipedia_how-to_and_information_pages" title="Wikipedia:Project namespace">how-to guide</a>.</b><br/><div style="font-size: 90%;">It explains concepts or processes used by the Wikipedia community. It is not one of <a href="/wiki/Wikipedia:Policies_and_guidelines" title="Wikipedia:Policies and guidelines">Wikipedia's policies or guidelines</a>, and may reflect varying levels of <a href="/wiki/Wikipedia:Consensus" title="Wikipedia:Consensus">consensus</a>.</div></div></td><td class="mbox-imageright"><style data-mw-deduplicate="TemplateStyles:r1252059228">.mw-parser-output .module-shortcutboxplain{float:right;margin:0 0 0 1em;border:1px solid var(--border-color-base,#a2a9b1);background-color:var(--background-color-base,#fff);padding:0.3em 0.6em 0.2em 0.6em;text-align:center;font-size:85%}.mw-parser-output .module-shortcutboxleft{float:left;margin:0 1em 0 0}.mw-parser-output .module-shortcutlist{display:inline-block;border-bottom:1px solid var(--border-color-base,#a2a9b1);margin-bottom:0.2em}.mw-parser-output .module-shortcutboxplain ul{font-weight:bold}.mw-parser-output .module-shortcutanchordiv{position:relative;top:-3em}.mw-parser-output li .module-shortcutanchordiv{float:right}.mw-parser-output .mbox-imageright .module-shortcutboxplain{padding:0.4em 1em 0.4em 1em;line-height:1.3;margin:0}</style><div class="module-shortcutanchordiv"><span id="H:CONEX"></span><span id="H:CX"></span></div><div class="module-shortcutboxplain noprint" role="note"><div class="module-shortcutlist"><a href="/wiki/Wikipedia:Shortcut" title="Wikipedia:Shortcut">Shortcuts</a></div><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li><span class="plainlinks"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=H:CONEX&redirect=no">H:CONEX</a></span></li><li><span class="plainlinks"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=H:CX&redirect=no">H:CX</a></span></li></ul></div></div></td></tr></tbody></table> <p>This page describes how to use various <a href="/wiki/Wikipedia:Parser_functions" class="mw-redirect" title="Wikipedia:Parser functions">parser functions</a> to display different results based on detected conditions in a page or <a href="/wiki/Help:Template" title="Help:Template">template</a>. </p><p>Here is a quick summary of these functions in terms of how they treat their input (the function names are linked to more detailed descriptions of them found below on this page): </p> <ul><li><code><a href="#if">#if</a></code> checks the truth value of a string</li> <li><code><a href="#ifeq">#ifeq</a></code> checks whether two strings or numbers are equal</li> <li><code><a href="#switch">#switch</a></code> compares a string to a set of possible values</li> <li><code><a href="#expr">#expr</a></code> evaluates a mathematical expression</li> <li><code><a href="#ifexpr">#ifexpr</a></code> evaluates a mathematical expression and acts on the truth value of the result</li> <li><code><a href="#iferror">#iferror</a></code> checks whether a string (often an expression inside of <code>#expr</code>) triggers a parser error</li> <li><code><a href="#ifexist">#ifexist</a></code> checks whether a page with a given title exists on the wiki (including image/media files)</li></ul> <p>For the use of these functions in tables, see <a href="/wiki/Help:Conditional_tables" title="Help:Conditional tables">Help:Conditional tables</a>. </p> <meta property="mw:PageProp/toc"/> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Summary" data-mw-thread-id="h-Summary"><span data-mw-comment-start="" id="h-Summary"></span>Summary<span data-mw-comment-end="h-Summary"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=1" title="Edit section: Summary"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The basic syntax (and use) of each function is as follows: </p> <ul><li><code>{{#if: <i>test string</i> | <i>value if true</i> | <i>value if false</i> }}</code> <dl><dd>(selects one of two values based on whether the test string is true or false)</dd></dl></li> <li><code>{{#ifeq: <i>string 1</i> | <i>string 2</i> | <i>value if equal</i> | <i>value if unequal</i> }}</code> <dl><dd>(selects one of two values based on whether the two strings are equal—a numerical comparison is done whenever that is possible)</dd></dl></li> <li><code>{{#switch: <i>test string</i> | <i>case1</i> = <i>value for case 1</i> | ... | <i>default</i> }}</code> <dl><dd>(chooses between multiple alternatives based on the value of the test string—basically equivalent to a chain of <code>#ifeq</code> tests, but <i>much</i> more efficient)</dd></dl></li> <li><code>{{#expr: <i>expression</i> }}</code> <dl><dd>(evaluates a given expression; see <a href="/wiki/Help:Calculation" title="Help:Calculation">Help:Calculation</a> for details)</dd></dl></li> <li><code>{{#ifexpr: <i>expression</i> | <i>value if true</i> | <i>value if false</i> }}</code> <dl><dd>(selects one of two values based on the truth value of an evaluated expression)</dd></dl></li> <li><code>{{#iferror: <i>test string</i> | <i>value if error</i> | <i>value if no error</i> }}</code> <dl><dd>(selects one of two values based on whether the test string generates a parser error)</dd></dl></li> <li><code>{{#ifexist: <i>page title</i> | <i>value if exists</i> | <i>value if doesn't exist</i> }}</code> <dl><dd>(selects one of two values depending on the existence of a page having the given title)</dd></dl></li></ul> <p><span class="anchor" id="Truth"></span>Note that "truth" is interpreted very differently by the string-based <code><a href="#if">#if</a></code> function and the numerically oriented functions <code><a href="#expr">#expr</a></code> and <code><a href="#ifexpr">#ifexpr</a></code>. A string is considered true if it contains at least one non-whitespace character (thus, for example, the <code>#if</code> function interprets the strings "0" and "FALSE" as true values, not false). Any string containing only whitespace or no characters at all will be treated as false (thus <code>#if</code> interprets " " and "", as well as undefined parameters, as false values). On the other hand, in the expressions evaluated by <code>#expr</code> and <code>#ifexpr</code>, Boolean operators like <code>and</code>, <code>or</code>, and <code>not</code> interpret the numerical value 0 as false and any other number as true. In terms of output, Boolean operations return 1 for a true value and 0 for false (and these are treated as ordinary numbers by the numerical operators). Non-numerical strings (including most uses of empty strings and undefined parameters) will cause <code>#expr</code> and <code>#ifexpr</code> to report an error. </p><p>Also note that all leading and trailing <a href="/wiki/Whitespace_character" title="Whitespace character">whitespace</a> within each of the parts of a parser function call gets stripped out, allowing the calls to be formatted with extra whitespace for better readability. For example: </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">xx</span><span class="p">|}}}</span> <span class="p">|</span> parameter xx value is true <span class="p">|</span> parameter xx value is false <span class="p">}}</span> </pre></div> <p>Here, only the spaces in the strings "parameter xx value is true" and "parameter xx value is false" are significant. All other whitespace is ignored. Thus, the construct above is equivalent to the following call: </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#if</span><span class="p">:{{{</span><span class="nv">xx</span><span class="p">|}}}|</span>parameter xx value is true<span class="p">|</span>parameter xx value is false<span class="p">}}</span> </pre></div> <p>In any part of a parser function call where a string is expected, one can use a literal string, a template call, a parser function call, or some other <a href="/wiki/Help:Magic_words" title="Help:Magic words">magic word</a>. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#if" data-mw-thread-id="h-Using_#if"><span id="Using_.23if"></span><span data-mw-comment-start="" id="h-Using_#if"></span><span id="if"></span>Using <code>#if</code><span data-mw-comment-end="h-Using_#if"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=2" title="Edit section: Using #if"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dd><i>See also: the <code>{{<a href="/wiki/Template:If" title="Template:If">if</a>}}</code> template</i></dd></dl> <p>The <code>#if</code> function selects one of two alternatives based on the truth value of a test string. </p> <dl><dd><b><code>{{#if: <i>test string</i> | <i>value if true</i> | <i>value if false</i> }}</code></b></dd></dl> <p><a href="#Truth">As explained above</a>, a string is considered true if it contains at least one non-whitespace character. Any string containing only whitespace or no characters at all will be treated as false. </p><p>Undefined parameter values are tricky: if the first positional parameter was not defined in the template call, then <code>{{{1}}}</code> will evaluate to the literal string "{{{1}}}" (i.e., the 7-character string containing three sets of curly braces around the number 1), which is a <i>true</i> value. (This problem exists for both <a href="/wiki/Help:Template#Handling_parameters" title="Help:Template">named and positional</a> parameters.) But <code>{{{1|}}}</code> will evaluate to the empty string (a <i>false</i> value) because the <a href="/wiki/Vertical_bar" title="Vertical bar">vertical bar</a> or pipe character, <code>"|"</code>, immediately following the parameter name specifies a default value (here an empty string because there is nothing between the pipe and the first closing curly brace) as a "fallback" value to be used if the parameter is undefined. </p><p>This function can be used to check whether a parameter has been passed to a template with a true value. </p><p>Examples: </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|}}}</span> <span class="p">|</span> first positional parameter has a true value <span class="p">|</span> first positional parameter has a false value (or no value) <span class="p">}}</span> <span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">xx</span><span class="p">|}}}</span> <span class="p">|</span> named parameter xx has a true value <span class="p">|</span> named parameter xx has a false value (or no value) <span class="p">}}</span> <span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">xx</span><span class="p">|}}}{{{</span><span class="nv">yy</span><span class="p">|}}}</span> <span class="p">|</span> either xx or yy has a true value, or both are true <span class="p">|</span> both xx and yy have a false value (or no value) <span class="p">}}</span> </pre></div> <p>Testing whether both of two parameters are true requires a little more effort. For example: </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">xx</span><span class="p">|}}}</span> <span class="p">|</span> <span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">yy</span><span class="p">|}}}</span> <span class="p">|</span> both xx and yy have true values <span class="p">|</span> xx is true but not yy <span class="p">}}</span> <span class="p">|</span> both xx and yy are false <span class="p">}}</span> </pre></div> <p>Note that nesting <code>#if</code> functions like this gets very resource-intensive very fast. On some wikis, even seven levels of nesting might exceed resource limits. </p><p>See the discussion of <code><a href="#ifeq">#ifeq</a></code> for how to detect whether a parameter has been defined regardless of whether its value is true or false. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#ifeq" data-mw-thread-id="h-Using_#ifeq"><span id="Using_.23ifeq"></span><span data-mw-comment-start="" id="h-Using_#ifeq"></span><span id="ifeq"></span>Using <code>#ifeq</code><span data-mw-comment-end="h-Using_#ifeq"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=3" title="Edit section: Using #ifeq"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dd><i>See also: the <code>{{<a href="/wiki/Template:Ifeq" title="Template:Ifeq">ifeq</a>}}</code> template</i></dd></dl> <p>The <code>#ifeq</code> function selects one of two alternatives based on whether two test strings are equal to each other. </p> <dl><dd><b><code>{{#ifeq: <i>string 1</i> | <i>string 2</i> | <i>value if equal</i> | <i>value if not equal</i> }}</code></b></dd></dl> <p>If both strings are valid numerical values, they are compared as numbers, rather than as literal strings: </p> <dl><dd><code>{{#ifeq: 01 | 1 | equal | not equal }}</code> → <b>equal</b></dd> <dd><code>{{#ifeq: x01 | x1 | equal | not equal }}</code> → <b>not equal</b></dd> <dd><code>{{#ifeq: 2.000 | 002 | equal | not equal }}</code> → <b>equal</b></dd> <dd><code>{{#ifeq: 2.5 | 2+.5 | equal | not equal }}</code> → <b>not equal</b> (arithmetic!)</dd> <dd><code>{{#ifeq: 2*10^3 | 2000 | equal | not equal }}</code> → <b>not equal</b> (arithmetic!)</dd> <dd><code>{{#ifeq: 2E3 | 2000 | equal | not equal }}</code> → <b>equal</b></dd></dl> <p>As seen in the 4th and 5th examples, mathematical expressions are <i>not</i> evaluated. They are treated as regular strings. But <code><a href="#expr">#expr</a></code> can be used to evaluate such expressions. </p> <dl><dd><code>{{#ifeq: {{#expr:2*10^3}} | 2000 | equal | not equal }}</code> → <b>equal</b></dd></dl> <p>String comparisons are <a href="/wiki/Case-sensitive" class="mw-redirect" title="Case-sensitive">case-sensitive</a>: </p> <dl><dd><code>{{#ifeq: King | king | equal | not equal }}</code> → <b>not equal</b></dd></dl> <p>For case-insensitive checking, use <a href="/wiki/Help:Magic_words#Formatting" title="Help:Magic words">the <code>{{lc:}}</code> or <code>{{uc:}}</code> function</a> to force the strings to all lower- or upper-case. This is most useful when dealing with parameter values: </p> <dl><dd><code>{{#ifeq: {{lc:King}} | king | equal | not equal }}</code> → <b>equal</b></dd> <dd><code>{{#ifeq: {{lc: {{{position}}} }} | top | code if true | code if false }}</code></dd></dl> <p>In the second example, the values "top", "Top", and "TOP" will all result in successful matches. </p><p>This parser function can be used to detect whether a template parameter is defined, even if it has been set to a false value. For example, to check whether the first positional parameter has been passed to a template (note that the strings "<code>+</code>" and "<code>-</code>" can be any two different non-whitespace strings): </p> <dl><dd><code>{{#ifeq: {{{1|+}}} | {{{1|-}}} | 1 is defined | 1 is undefined }}</code></dd></dl> <p>To be specific, here's what this code generates when called in the following ways: </p> <dl><dd><code>{{<var>template-name</var>}}</code> → <b>1 is undefined</b></dd> <dd><code>{{<var>template-name</var>|}}</code> → <b>1 is defined</b></dd> <dd><code>{{<var>template-name</var>|1=}}</code> → <b>1 is defined</b></dd> <dd><code>{{<var>template-name</var>|1=foo}}</code> → <b>1 is defined</b></dd></dl> <p>See <a href="https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions##ifeq" class="extiw" title="mw:Help:Extension:ParserFunctions">mw:Help:Extension:ParserFunctions##ifeq</a> for more details, including possible counterintuitive results due to the way this function is implemented. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#switch" data-mw-thread-id="h-Using_#switch"><span id="Using_.23switch"></span><span data-mw-comment-start="" id="h-Using_#switch"></span><span id="switch"></span>Using <code>#switch</code><span data-mw-comment-end="h-Using_#switch"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=4" title="Edit section: Using #switch"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <code>#switch</code> function selects between multiple alternatives based on an input string. </p> <dl><dd><b><code>{{#switch: <i>test string</i> | <i>case1</i> = <i>value for case 1</i> | ... | <i>default value</i> }}</code></b></dd></dl> <p>Equivalent to the <a href="/wiki/Switch_statement" title="Switch statement">switch statement</a> found in some programming languages, it is a convenient way of dealing with multiple cases without having to chain lots of <code>#if</code> functions together. However, note that performance suffers when there are more than 100 alternatives. Placing common values earlier in the list of cases can cause the function to execute significantly faster. </p><p>For each case, either side of the equals sign "<code>=</code>" can be a simple string, a call to a parser function (including <code>#expr</code> to evaulate expressions), or a template call. If any cases are not associated with a value (i.e., no equals sign is used), the next specified value will be used. This allows multiple cases to share the same value without having to specify that value repeatedly (as seen in the example below). </p><p>If no matching case is found, then the default value is used. This is usually specified last with no associated "<i>case</i>" value, as seen in the syntax summary above, but it can also be specified at any point after the test string if the construct <code>| #default = <i>value</i></code> is used (see the second example below). If no default is specified in either way, then a null string will be returned when no cases match the input string. </p><p>This function in particular benefits from being set up in a multiline format. </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#switch</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">x</span><span class="p">|}}}</span> <span class="p">|</span><span class="nl"> 1 </span><span class="o">=</span> one <span class="p">|</span><span class="nl"> 2 </span><span class="o">=</span> two <span class="p">|</span><span class="nl"> 3 </span><span class="o">=</span> three <span class="p">|</span><span class="nl"> 4 </span><span class="o">=</span> four <span class="p">|</span> 5 <span class="p">|</span> 6 <span class="p">|</span><span class="nl"> 7 </span><span class="o">=</span> in the range 5 to 7 <span class="p">|</span> other <span class="p">}}</span> </pre></div> <p>Here, if the value of the template parameter <code>x</code> is the string "1", then the output will be the string "one"; if "2", then "two"; and so forth. But for any of the values "5", "6" or "7", the output will be the string "in the range 5 to 7". For any other value, or a null value, it will return the string "other". </p><p>The following example is equivalent to the previous one: </p> <div class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><pre><span></span><span class="p">{{</span><span class="nf">#switch</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">x</span><span class="p">|}}}</span> <span class="p">|</span><span class="nl"> #default </span><span class="o">=</span> other <span class="p">|</span><span class="nl"> 1 </span><span class="o">=</span> one <span class="p">|</span><span class="nl"> 2 </span><span class="o">=</span> two <span class="p">|</span><span class="nl"> 3 </span><span class="o">=</span> three <span class="p">|</span><span class="nl"> 4 </span><span class="o">=</span> four <span class="p">|</span> 5<span class="p">|</span>6<span class="p">|</span><span class="nl">7 </span><span class="o">=</span> in the range 5 to 7 <span class="p">}}</span> </pre></div> <p>See <a href="/wiki/Help:Switch_parser_function" title="Help:Switch parser function">Help:Switch parser function</a> for a full description and more examples. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#expr" data-mw-thread-id="h-Using_#expr"><span id="Using_.23expr"></span><span data-mw-comment-start="" id="h-Using_#expr"></span><span id="expr"></span>Using <code>#expr</code><span data-mw-comment-end="h-Using_#expr"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=5" title="Edit section: Using #expr"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <code>#expr</code> function evaluates mathematical (including Boolean) expressions. While not itself a conditional function, it is often used inside of those functions, so it is briefly described here. See <a class="external text" href="https://www.mediawiki.org/wiki/Manual:Expr_parser_function_syntax">Manual:Expr parser function syntax</a> for further details. </p> <dl><dd><b><code>{{#expr: <i>expression</i> }}</code></b></dd></dl> <p>Unlike the <code><a href="#if">#if</a></code> function, all values in the <code><i>expression</i></code> evaluated by <code>#expr</code> are assumed to be numerical. It does not work with arbitrary strings. For the purpose of its Boolean operations (e.g., <code>and</code>, <code>or</code>, and <code>not</code>), false is represented by 0 and true by 1; these values are treated as regular numbers by the numerical operators. As input, the Boolean operators treat 0 as false and every other number as true. If any non-numerical strings are used, an error will result. </p><p>Examples: </p> <dl><dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> ( <span class="p">{{{</span><span class="nv">1</span><span class="p">}}}</span>+<span class="p">{{{</span><span class="nv">xshift</span><span class="p">}}}</span> - 6 ) * 18.4 <span class="p">}}</span></code></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> ln(7)^3 - abs(-0.344) + floor(5/3) round 3 <span class="p">}}</span></code></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">n</span><span class="p">}}}</span>>0 and <span class="p">{{{</span><span class="nv">n</span><span class="p">}}}</span><1.0 <span class="p">}}</span></code></dd></dl> <p>Note that these examples assume that all parameters referred to are defined and have numerical values. If this is not the case, errors will occur. See <code><a href="#iferror">#iferror</a></code> for one way to handle errors. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#ifexpr" data-mw-thread-id="h-Using_#ifexpr"><span id="Using_.23ifexpr"></span><span data-mw-comment-start="" id="h-Using_#ifexpr"></span><span id="ifexpr"></span>Using <code>#ifexpr</code><span data-mw-comment-end="h-Using_#ifexpr"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=6" title="Edit section: Using #ifexpr"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <code>#ifexpr</code> function evaluates an expression in exactly the same way <code><a href="#expr">#expr</a></code> does (see the explanation of that function for details), but returns one of two possible values depending on the truth value of the result. </p> <dl><dd><b><code>{{#ifexpr: <i>expression</i> | <i>value if true</i> | <i>value if false</i> }}</code></b></dd></dl> <p>Examples: </p> <dl><dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#ifexpr</span><span class="p">:</span> ( <span class="p">{{{</span><span class="nv">1</span><span class="p">}}}</span> + <span class="p">{{{</span><span class="nv">2</span><span class="p">}}}</span> ) * 2.63 > 45 <span class="p">|</span> above 45 <span class="p">|</span> not above 45 <span class="p">}}</span></code></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#ifexpr</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">}}}</span> > 0 and <span class="p">{{{</span><span class="nv">1</span><span class="p">}}}</span> < 1.0 or <span class="p">{{</span><span class="nf">#ifeq</span><span class="p">:{{{</span><span class="nv">decimal</span><span class="p">}}}|</span>yes<span class="p">}}</span> <span class="p">|</span> is decimal <span class="p">|</span> not decimal <span class="p">}}</span></code></dd></dl> <p>As <a href="#Truth">explained above</a>, for the purposes of this function, 0 is false and any other numerical value is true. </p> <dl><dd><code>{{#ifexpr: 0 | yes | no }}</code> → <b>no</b></dd> <dd><code>{{#ifexpr: 1 | yes | no }}</code> → <b>yes</b></dd> <dd><code>{{#ifexpr: 2 | yes | no }}</code> → <b>yes</b></dd></dl> <p>An empty input expression evaluates to false. </p> <dl><dd><code>{{#ifexpr: | yes | no }}</code> → <b>no</b></dd></dl> <p>But invalid input, including input containing non-numerical strings, will display an error message. </p> <dl><dd><code>{{#ifexpr: = | yes | no }}</code> → <b><strong class="error">Expression error: Unexpected = operator</strong></b></dd> <dd><code>{{#ifexpr: A=B | yes | no }}</code> → <b><strong class="error">Expression error: Unrecognized word "a".</strong></b></dd></dl> <p>Under normal circumstances, the function <code>#ifexpr</code> is equivalent to using the following construct with <code><a href="#ifeq">#ifeq</a></code> and <code><a href="#expr">#expr</a></code> (note the reversal of the "true" and "false" output values, since we are comparing the input result to "0"): </p> <dl><dd><code>{{#ifeq: {{#expr: <i>expression</i> }} | 0 | <i>value if false</i> | <i>value if true</i> }}</code></dd></dl> <p>But any error message generated by <code>#expr</code> will be seen by <code>#ifeq</code> as an ordinary string that is not equal to "0", and thus the <code><i>value if true</i></code> will be output. </p> <dl><dd><code>{{#ifeq: {{#expr: = }} | 0 | yes | no }}</code> → <b>no</b></dd></dl> <p>Either or both of the output values may be omitted (or left empty), in which case (assuming the "missing" branch of the construct is reached) no output results. </p> <dl><dd><code>{{#ifexpr: 1 > 0 | yes }}</code> → <b>yes</b></dd> <dd><code>{{#ifexpr: 1 > 0 | | no }}</code> → <b></b></dd></dl> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238436933"><table class="plainlinks ombox ombox-notice" role="presentation"><tbody><tr><td class="mbox-image"><figure class="mw-halign-right" typeof="mw:File"><a href="/wiki/File:Crystal_Clear_app_ktip.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Crystal_Clear_app_ktip.svg/40px-Crystal_Clear_app_ktip.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Crystal_Clear_app_ktip.svg/60px-Crystal_Clear_app_ktip.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Crystal_Clear_app_ktip.svg/80px-Crystal_Clear_app_ktip.svg.png 2x" data-file-width="128" data-file-height="128"/></a><figcaption></figcaption></figure></td><td class="mbox-text"><div><span style="font-size:110%;"><b>Tip</b></span></div> To make comparisons based on dates (e.g., if the current date and time is after some other date and time), first convert the time(s) to the number of seconds after January 1, 1970, using the function <a href="/wiki/Help:Time_function" title="Help:Time function">{{#time: U }}</a>, then compare (or add, subtract, etc.) those numerical values.</td></tr></tbody></table> <p>See <a href="https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions##ifexpr" class="extiw" title="mw:Help:Extension:ParserFunctions">mw:Help:Extension:ParserFunctions##ifexpr</a> for more details, including possible counterintuitive results due to the way this function is implemented. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#iferror" data-mw-thread-id="h-Using_#iferror"><span id="Using_.23iferror"></span><span data-mw-comment-start="" id="h-Using_#iferror"></span><span id="iferror"></span>Using <code>#iferror</code><span data-mw-comment-end="h-Using_#iferror"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=7" title="Edit section: Using #iferror"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <code>#iferror</code> function selects one of two alternatives depending on whether its input triggers an error. </p> <dl><dd><b><code>{{#iferror: <i>test string</i> | <i>value if error</i> | <i>value if correct</i> }}</code></b></dd></dl> <p>The test string is typically a call to <code><a href="#expr">#expr</a></code> or some other parser function, but can be plain text or a template call, in which case an error would be triggered by any HTML object with <code>class="error"</code> or any of various <a href="https://www.mediawiki.org/wiki/Help:Templates" class="extiw" title="mw:Help:Templates">template</a> errors such as loops and recursions, or some other "failsoft" parser error. </p><p>One or both of the return values can be omitted. If the <code><i>value if correct</i></code> is omitted, the test string is returned if it is not erroneous. If the <code><i>value if error</i></code> is also omitted, an empty string is returned on an error: </p> <dl><dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + 2 <span class="p">}}</span> <span class="p">|</span> error <span class="p">|</span> correct <span class="p">}}</span></code> → <b>correct</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + X <span class="p">}}</span> <span class="p">|</span> error <span class="p">|</span> correct <span class="p">}}</span></code> → <b>error</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + 2 <span class="p">}}</span> <span class="p">|</span> error <span class="p">}}</span></code> → <b>3</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + X <span class="p">}}</span> <span class="p">|</span> error <span class="p">}}</span></code> → <b>error</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + 2 <span class="p">}}</span> <span class="p">}}</span></code> → <b>3</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> 1 + X <span class="p">}}</span> <span class="p">}}</span></code> → <b></b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#expr</span><span class="p">:</span> . <span class="p">}}</span> <span class="p">|</span> error <span class="p">|</span> correct <span class="p">}}</span></code> → <b>correct</b></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#iferror</span><span class="p">:</span> <span class="p"><</span><span class="nt">strong</span><span class="w"> </span><span class="na">class</span><span class="o">=</span><span class="s2">"error"</span><span class="p">></span>a<span class="p"></</span><span class="nt">strong</span><span class="p">></span> <span class="p">|</span> error <span class="p">|</span> correct <span class="p">}}</span></code> → <b>error</b></dd></dl> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Using_#ifexist" data-mw-thread-id="h-Using_#ifexist"><span id="Using_.23ifexist"></span><span data-mw-comment-start="" id="h-Using_#ifexist"></span><span id="ifexist"></span>Using <code>#ifexist</code><span data-mw-comment-end="h-Using_#ifexist"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=8" title="Edit section: Using #ifexist"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1252059228"><div class="module-shortcutanchordiv"><span id="HELP:ifexist"></span></div><div class="module-shortcutboxplain noprint" role="note"><div class="module-shortcutlist"><a href="/wiki/Wikipedia:Shortcut" title="Wikipedia:Shortcut">Shortcut</a></div><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span class="plainlinks"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Help:Ifexist&redirect=no">HELP:ifexist</a></span></li></ul></div></div> <p>The <code>#ifexist</code> function selects one of two alternatives depending on whether a page exists at the specified title. </p> <dl><dd><b><code>{{#ifexist: <i>page title</i> | <i>value if page exists</i> | <i>value if page doesn't exist</i> }}</code></b></dd></dl> <p>The page can be in any <a href="/wiki/Help:Namespace" class="mw-redirect" title="Help:Namespace">namespace</a>, so it can be an article or "content page", an image or other media file, a category, etc. The actual content of the page is irrelevant, so it may be empty or a <a href="/wiki/Help:Redirect" title="Help:Redirect">redirect</a>. Titles that would result in <a href="/wiki/Redlinks" class="mw-redirect mw-disambig" title="Redlinks">redlinks</a> do not exist (and, as with redlinks, checking for the existence of a nonexistent page causes the title to appear on <a href="/wiki/Special:WantedPages" title="Special:WantedPages">Special:WantedPages</a>). </p><p>The checking is extremely fast, but has been limited to 500 instances per page because it is considered an "<a href="https://www.mediawiki.org/wiki/Manual:$wgExpensiveParserFunctionLimit" class="extiw" title="mw:Manual:$wgExpensiveParserFunctionLimit">expensive parser function</a>". (However, multiple checks of the <i>same</i> title on the same page do not count as multiple instances, because the results of the first check is cached and reused for the subsequent checks.) </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Checking_for_template_parameters" data-mw-thread-id="h-Checking_for_template_parameters"><span data-mw-comment-start="" id="h-Checking_for_template_parameters"></span><span id="Conditionals_for_templates"></span>Checking for template parameters<span data-mw-comment-end="h-Checking_for_template_parameters"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=9" title="Edit section: Checking for template parameters"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A common idiom encountered in template coding is the "chain of fallback values", as seen in this example: </p> <dl><dd><code>{{{1|<style data-mw-deduplicate="TemplateStyles:r1239334494">@media screen{html.skin-theme-clientpref-night .mw-parser-output div:not(.notheme)>.tmp-color,html.skin-theme-clientpref-night .mw-parser-output p>.tmp-color,html.skin-theme-clientpref-night .mw-parser-output table:not(.notheme) .tmp-color{color:inherit!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output div:not(.notheme)>.tmp-color,html.skin-theme-clientpref-os .mw-parser-output p>.tmp-color,html.skin-theme-clientpref-os .mw-parser-output table:not(.notheme) .tmp-color{color:inherit!important}}</style><span class="tmp-color" style="color:purple">{{{url|<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239334494"><span class="tmp-color" style="color:darkgreen">{{{URL|}}}</span>}}}</span>}}}</code></dd></dl> <p>Here, if the first positional parameter is defined, then its value will be used. If it is undefined, then the parameter named <code>url</code> will be checked and if it is defined, then its value will be used. If both the first positional parameter and <code>url</code> are undefined, then the parameter named <code>URL</code> is checked: if it is defined, its value is used; if not, then the empty string will be used. </p><p>The problem is, this construct tends to be interpreted as being equivalent to: </p> <dl><dd><code>{{#if: {{{1|}}} | {{{1}}} | <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239334494"><span class="tmp-color" style="color:purple">{{#if: {{{url|}}} | {{{url}}} | <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239334494"><span class="tmp-color" style="color:darkgreen">{{#if: {{{URL|}}} | {{{URL}}} }}</span> }}</span> }}</code></dd></dl> <p>and it is <b>not</b>. The difference is that the first construct, using default values, depends on the <i>definedness</i> of the parameters, whereas the second construct, using <code>#if</code> functions, depends on the <i>truth value</i> of the parameters. These are two very different things. </p><p>If any of the parameters in the chain of fallback values (in the first construct) have been set to an empty value (or only whitespace) in the template call, then that empty value will be used instead of "falling back" to the next parameter in the chain. So, for example, if the template is called in either of these two ways: </p> <dl><dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nt">template-name</span><span class="p">||</span><span class="nl">url</span><span class="o">=</span>https://example.com/<span class="p">}}</span></code></dd> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nt">template-name</span><span class="p">|</span><span class="nl">url</span><span class="o">=</span>https://example.com/<span class="p">|}}</span></code></dd></dl> <p>The first positional parameter <i>has</i> been defined: its value is the empty string. Thus, the value of <code>url</code> is irrelevant. The template never "gets to" that value. </p><p>Similarly, if the template is called in this way: </p> <dl><dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nt">template-name</span><span class="p">|</span><span class="nl">url</span><span class="o">=</span><span class="p">|</span><span class="nl">URL</span><span class="o">=</span>https://example.com/<span class="p">}}</span></code></dd></dl> <p>The empty value of <code>url</code> will be used instead of the value of <code>URL</code>. </p><p>These examples might seem a bit contrived, since they rely on the template being called in "the wrong way". But it is surprisingly easy to run across cases where these problems occur with perfectly reasonable template calls (especially if there is a "hierarchy" of templates, where one template calls another, passing on the values of its parameters to the parameters of the "lower-level" template—in such cases, one will often end up with defined-but-empty parameter values). </p><p>Because of issues like this, template coders sometimes find themselves needing to distinguish between different combinations of three states: defined-and-non-blank, defined-and-blank, and undefined. This can be done in the following ways (the first positional parameter is used here, but named parameters work the same way). </p> <dl><dt>Defined-and-non-blank vs. undefined or defined-and-blank</dt> <dd><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|}}}</span> <span class="p">|</span> 1 is defined and contains non-whitespace <span class="p">|</span> 1 is undefined, empty, or contains only whitespace <span class="p">}}</span></code></dd></dl> <dl><dt>Defined (whether non-blank or blank) vs. undefined</dt> <dd>The following are equivalent alternatives: <ul><li><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#ifeq</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|</span>+<span class="p">}}}</span> <span class="p">|</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|</span>-<span class="p">}}}</span> <span class="p">|</span> 1 is defined (and possibly empty or only-whitespace) <span class="p">|</span> 1 is undefined <span class="p">}}</span></code></li> <li><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#ifeq</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|</span>/<span class="p">}}}{{{</span><span class="nv">1</span><span class="p">|}}}</span> <span class="p">|</span> / <span class="p">|</span> 1 is undefined <span class="p">|</span> 1 is defined (and possibly empty or only-whitespace) <span class="p">}}</span></code></li> <li><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|</span>/<span class="p">}}}</span> <span class="p">|</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|}}}</span> <span class="p">|</span> / <span class="p">}}</span> <span class="p">|</span> 1 is defined (and possibly empty or only-whitespace) <span class="p">|</span> 1 is undefined <span class="p">}}</span></code></li></ul></dd></dl> <p>Note that the <code>+</code> and <code>-</code> characters can be any two different non-whitespace characters. Also, if you just want to use the value of the parameter when it's defined and some other value when it's undefined, you can use the simpler "fallback" construct: </p> <dl><dd><code>{{{1|<i>some other value</i>}}}</code></dd></dl> <dl><dt>Defined-and-non-blank vs. defined-and-blank vs. undefined</dt> <dd>The following are equivalent alternatives: <ul><li><code>{{#ifeq: {{{1|+}}} | {{{1|-}}} | 1 is defined <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239334494"><span class="tmp-color" style="color:purple">{{#if: {{{1|}}} | and non-blank | and blank }}</span> | 1 undefined }}</code></li> <li><code class="mw-highlight mw-highlight-lang-wikitext mw-content-ltr" dir="ltr"><span class="p">{{</span><span class="nf">#if</span><span class="p">:</span> <span class="p">{{{</span><span class="nv">1</span><span class="p">|</span>/<span class="p">}}}</span> <span class="p">|</span> <span class="p">{{</span><span class="nf">#if</span><span class="p">:{{{</span><span class="nv">1</span><span class="p">|}}}</span> <span class="p">|</span> 1 is defined and non-blank <span class="p">|</span> 1 is undefined <span class="p">}}</span> <span class="p">|</span> 1 is defined and blank <span class="p">}}</span></code></li></ul></dd></dl> <p>If you don't care about the undefined case, you can remove the "<code>|1 undefined</code>" in both examples. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="Variadic_templates" data-mw-thread-id="h-Variadic_templates"><span data-mw-comment-start="" id="h-Variadic_templates"></span>Variadic templates<span data-mw-comment-end="h-Variadic_templates"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=10" title="Edit section: Variadic templates"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Wikitext syntax does not allow natively to create truly <a href="/wiki/Variadic_template" title="Variadic template">variadic templates</a>, but only pseudo-variadic ones, that check the incoming parameters one by one until a certain fixed amount. It is possible to break this limitation however by using dedicated modules. For simple cases, {{<a href="/wiki/Module:Separated_entries" title="Module:Separated entries">#invoke:separated entries</a>|main}} allows to expand all sequential parameters blindly and has the ability to set custom delimiters. For more complex cases, {{<a href="/wiki/Module:Params" title="Module:Params">#invoke:params</a>}} allows to count, list, map, filter and propagate all incoming parameters without knowing their number in advance. </p> <div class="mw-heading mw-heading2 ext-discussiontools-init-section"><h2 id="See_also" data-mw-thread-id="h-See_also"><span data-mw-comment-start="" id="h-See_also"></span>See also<span data-mw-comment-end="h-See_also"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Help:Conditional_expressions&action=edit&section=11" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Help:Conditional_tables" title="Help:Conditional tables">Help:Conditional tables</a></li> <li><a href="https://www.mediawiki.org/wiki/Help:Extension:ParserFunctions" class="extiw" title="mw:Help:Extension:ParserFunctions">mw:Help:Extension:ParserFunctions</a>, a longer and more technical help page at MediaWiki.org</li> <li><a href="/wiki/Conditional_(computer_programming)" title="Conditional (computer programming)">Conditional (computer programming)</a></li> <li><a href="/wiki/Relational_operator" title="Relational operator">Relational operator</a></li> <li><a href="/wiki/Help:Template" title="Help:Template">Help:Template</a> and <a href="/wiki/Wikipedia:Template_sandbox_and_test_cases" title="Wikipedia:Template sandbox and test cases">Wikipedia:Template sandbox and test cases</a></li> <li><a href="https://meta.wikimedia.org/wiki/Help:Advanced_templates" class="extiw" title="m:Help:Advanced templates">m:Help:Advanced templates</a></li> <li><a href="/wiki/Category:If-then-else_templates" title="Category:If-then-else templates">Category:If-then-else templates</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Wikipedia_technical_help" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2" style="text-align: center;"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Wikipedia_technical_help" title="Template:Wikipedia technical help"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Wikipedia_technical_help" title="Template talk:Wikipedia technical help"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Wikipedia_technical_help" title="Special:EditPage/Template:Wikipedia technical help"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Wikipedia_technical_help" style="font-size:114%;margin:0 4em"><a href="/wiki/Help:Directory#Technical_help" title="Help:Directory">Wikipedia technical help</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2" style="text-align: center;"><div><b>Get personal technical help at <a href="/wiki/Wikipedia:Teahouse" title="Wikipedia:Teahouse">the Teahouse</a>, <a href="/wiki/Wikipedia:Help_desk" title="Wikipedia:Help desk">help desk</a>, <a href="/wiki/Wikipedia:Village_pump_(technical)" title="Wikipedia:Village pump (technical)">village pump (technical)</a>, <a href="/wiki/Help:Introduction_to_talk_pages/1" title="Help:Introduction to talk pages/1">talk pages</a> or <a href="/wiki/Wikipedia:IRC" title="Wikipedia:IRC">IRC</a>.</b></div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Wikipedia:FAQ/Technical" title="Wikipedia:FAQ/Technical">General<br/>technical help</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Wikipedia:Browser_notes" title="Wikipedia:Browser notes">Browser notes</a> <ul><li><a href="/wiki/Wikipedia:Bypass_your_cache" title="Wikipedia:Bypass your cache">Bypass cache</a></li> <li><a href="/wiki/Wikipedia:Keyboard_shortcuts" class="mw-redirect" title="Wikipedia:Keyboard shortcuts">Keyboard shortcuts</a></li></ul></li> <li><a href="/wiki/Help:Editing" title="Help:Editing">Editing</a> <ul><li><a href="/wiki/Help:CharInsert" title="Help:CharInsert">CharInsert</a></li> <li><a href="/wiki/Help:Edit_conflict" title="Help:Edit conflict">Edit conflict</a></li> <li><a href="/wiki/Help:Edit_toolbar" title="Help:Edit toolbar">Edit toolbar</a></li> <li><a href="/wiki/Help:Reverting" title="Help:Reverting">Reverting</a></li></ul></li> <li><a href="/wiki/Wikipedia:How_to_create_a_page" title="Wikipedia:How to create a page">How to create a page</a></li> <li><a href="/wiki/Wikipedia:IRC" title="Wikipedia:IRC">IRC</a> <ul><li><a href="/wiki/Wikipedia:IRC/Tutorial" title="Wikipedia:IRC/Tutorial">Tutorial</a></li></ul></li> <li><a href="/wiki/Help:Mobile_access" title="Help:Mobile access">Mobile access</a></li> <li><a href="/wiki/Help:Multilingual_support" title="Help:Multilingual support">Multilingual support</a></li> <li><a href="/wiki/Help:Page_history" title="Help:Page history">Page history</a></li> <li><a href="/wiki/Help:Page_information" title="Help:Page information">Page information</a></li> <li><a href="/wiki/Wikipedia:Page_name" title="Wikipedia:Page name">Page name</a> <ul><li><a href="/wiki/Help:Page_name" title="Help:Page name">Help</a></li></ul></li> <li><a href="/wiki/Help:Printing" title="Help:Printing">Printing</a></li> <li><a href="/wiki/Wikipedia:Software_notices" title="Wikipedia:Software notices">Software notices</a> <ul><li><a href="/wiki/Wikipedia:Editnotice" title="Wikipedia:Editnotice">Editnotice</a></li></ul></li> <li><a href="/wiki/Help:Special_characters" title="Help:Special characters">Special Characters</a> <ul><li><a href="/wiki/Help:Entering_special_characters" title="Help:Entering special characters">Entering</a></li></ul></li> <li><a href="/wiki/Wikipedia:User_access_levels" title="Wikipedia:User access levels">User access levels</a></li> <li><a href="/wiki/Wikipedia:VisualEditor" title="Wikipedia:VisualEditor">VisualEditor</a> <ul><li><a href="/wiki/Help:VisualEditor" title="Help:VisualEditor">Help</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Special:SpecialPages" title="Special:SpecialPages">Special<br/>page</a>-related</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Special_page" title="Help:Special page">Special page help</a></li> <li><a href="/wiki/Help:AllPages" title="Help:AllPages">AllPages</a></li> <li><a href="/wiki/Wikipedia:Edit_filter" title="Wikipedia:Edit filter">Edit filter</a></li> <li><a href="/wiki/Wikipedia:Emailing_users" title="Wikipedia:Emailing users">Emailing users</a></li> <li><a href="/wiki/Help:Logging_in" title="Help:Logging in">Logging in</a> <ul><li><a href="/wiki/Help:Reset_password" title="Help:Reset password">Reset passwords</a></li></ul></li> <li><a href="/wiki/Help:Log" title="Help:Log">Logs</a></li> <li><a href="/wiki/Wikipedia:Moving_a_page" title="Wikipedia:Moving a page">Moving a page</a> <ul><li><a href="/wiki/Wikipedia:History_merging" title="Wikipedia:History merging">History merging</a></li> <li><a href="/wiki/Help:When_to_place_technical_requests_in_%22Administrator_needed%22" title="Help:When to place technical requests in "Administrator needed"">Non-admin and admin-only page moves</a></li></ul></li> <li><a href="/wiki/Help:Notifications" title="Help:Notifications">Notifications/Echo</a> <ul><li><a href="/wiki/Help:Notifications/FAQ" title="Help:Notifications/FAQ">FAQ</a></li></ul></li> <li><a href="/wiki/Wikipedia:Page_Curation/Help" title="Wikipedia:Page Curation/Help">Page Curation</a></li> <li><a href="/wiki/Help:Import" title="Help:Import">Page import</a></li> <li><a href="/wiki/Wikipedia:Pending_changes" title="Wikipedia:Pending changes">Pending changes</a></li> <li><a href="/wiki/Wikipedia:Random" title="Wikipedia:Random">Random pages</a></li> <li><a href="/wiki/Help:Recent_changes" title="Help:Recent changes">Recent changes</a></li> <li><a href="/wiki/Help:Related_changes" title="Help:Related changes">Related changes</a></li> <li><a href="/wiki/Help:Searching" title="Help:Searching">Searching</a> <ul><li><a href="/wiki/Help:Linksearch" title="Help:Linksearch">Linksearch</a></li></ul></li> <li><a href="/wiki/Wikipedia:Tags" title="Wikipedia:Tags">Tags</a></li> <li><a href="/wiki/Help:User_contributions" title="Help:User contributions">User contributions</a></li> <li><a href="/wiki/Help:Watchlist" title="Help:Watchlist">Watchlist</a></li> <li><a href="/wiki/Help:What_links_here" title="Help:What links here">What links here</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Help:Wikitext" title="Help:Wikitext">Wikitext</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Wikitext" title="Help:Wikitext">Wikitext</a> <ul><li><a href="/wiki/Help:Cheatsheet" title="Help:Cheatsheet">Cheatsheet</a></li></ul></li> <li><a href="/wiki/Help:Columns" title="Help:Columns">Columns</a></li> <li><a href="/wiki/Help:Line-break_handling" title="Help:Line-break handling">Line-break handling</a></li> <li><a href="/wiki/Help:List" title="Help:List">Lists</a></li> <li><a href="/wiki/Help:Magic_words" title="Help:Magic words">Magic words</a> <ul><li><a href="/wiki/Help:Magic_words_for_beginners" title="Help:Magic words for beginners">For beginners</a></li> <li><a class="mw-selflink selflink">Conditional expressions</a></li> <li><a href="/wiki/Help:Switch_parser_function" title="Help:Switch parser function">Switch parser function</a></li> <li><a href="/wiki/Help:Time_function" title="Help:Time function">Time function</a></li></ul></li> <li><a href="/wiki/Help:Redirect" title="Help:Redirect">Redirects</a></li> <li><a href="/wiki/Help:Section" title="Help:Section">Sections and TOCs</a></li> <li><a href="/wiki/Help:Table" title="Help:Table">Tables</a> <ul><li><a href="/wiki/Help:Introduction_to_tables_with_Wiki_Markup/1" title="Help:Introduction to tables with Wiki Markup/1">Introduction</a></li> <li><a href="/wiki/Help:Basic_table_markup" title="Help:Basic table markup">Basics</a></li> <li><a href="/wiki/Help:Advanced_table_formatting" title="Help:Advanced table formatting">Advanced table formatting</a></li> <li><a href="/wiki/Help:Collapsing" class="mw-redirect" title="Help:Collapsing">Collapsing</a></li> <li><a href="/wiki/Help:Conditional_tables" title="Help:Conditional tables">Conditional tables</a></li> <li><a href="/wiki/Help:Sortable_tables" title="Help:Sortable tables">Sortable tables</a></li></ul></li> <li><a href="/wiki/Help:Using_colours" title="Help:Using colours">Using colours</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Help:Link" title="Help:Link">Links</a> and <a href="/wiki/Help:Diff" title="Help:Diff">diffs</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Link" title="Help:Link">Links</a> <ul><li><a href="/wiki/Help:Interlanguage_links" title="Help:Interlanguage links">Interlanguage</a></li> <li><a href="/wiki/Help:Interwiki_linking" title="Help:Interwiki linking">Interwiki</a></li> <li><a href="/wiki/Help:Permanent_link" title="Help:Permanent link">Permanent</a></li></ul></li> <li><a href="/wiki/Help:Diff" title="Help:Diff">Diffs</a> <ul><li><a href="/wiki/Wikipedia:Simplest_diff_guide" title="Wikipedia:Simplest diff guide">Simplest diff guide</a></li> <li><a href="/wiki/Wikipedia:Simple_diff_and_link_guide" title="Wikipedia:Simple diff and link guide">Simple diff and link guide</a></li> <li><a href="/wiki/Wikipedia:Complete_diff_and_link_guide" title="Wikipedia:Complete diff and link guide">Complete diff and link guide</a></li></ul></li> <li><a href="/wiki/Help:Colon_trick" title="Help:Colon trick">Colon trick</a></li> <li><a href="/wiki/Help:Link_color" title="Help:Link color">Link color</a></li> <li><a href="/wiki/Help:Pipe_trick" title="Help:Pipe trick">Pipe trick</a></li> <li><a href="/wiki/Help:URL" title="Help:URL">URLs</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Wikipedia:Media" class="mw-disambig" title="Wikipedia:Media">Media</a> files: images,<br/>videos and sounds</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Media" title="Help:Media">Media help</a></li> <li><a href="/wiki/Help:Files" title="Help:Files">Files</a> <ul><li><a href="/wiki/Help:Creation_and_usage_of_media_files" title="Help:Creation and usage of media files">Creation and usage</a></li> <li><a href="/wiki/Wikipedia:Moving_files_to_Commons" title="Wikipedia:Moving files to Commons">Moving files to Commons</a></li></ul></li> <li><a href="/wiki/Wikipedia:Images" title="Wikipedia:Images">Images</a> <ul><li><a href="/wiki/Help:Introduction_to_images_with_Wiki_Markup/1" title="Help:Introduction to images with Wiki Markup/1">Introduction to images</a></li> <li><a href="/wiki/Help:Pictures" title="Help:Pictures">Picture tutorial</a></li> <li><a href="/wiki/Wikipedia:Preparing_images_for_upload" title="Wikipedia:Preparing images for upload">Preparing images for upload</a></li> <li><a href="/wiki/Wikipedia:Uploading_images" title="Wikipedia:Uploading images">Uploading images</a></li> <li><a href="/wiki/Help:Options_to_hide_an_image" title="Help:Options to hide an image">Options to hide an image</a></li> <li><a href="/wiki/Wikipedia:Extended_image_syntax" title="Wikipedia:Extended image syntax">Extended image syntax</a></li> <li><a href="/wiki/Wikipedia:SVG_help" title="Wikipedia:SVG help">SVG help</a></li></ul></li> <li><a href="/wiki/Help:Gallery_tag" title="Help:Gallery tag">Gallery tag</a></li> <li><a href="/wiki/Wikipedia:Graphics_tutorials" title="Wikipedia:Graphics tutorials">Graphics tutorials</a> <ul><li><a href="/wiki/Wikipedia:Basic_bitmap_image_editing" title="Wikipedia:Basic bitmap image editing">Basic bitmap image editing</a></li> <li><a href="/wiki/Wikipedia:How_to_improve_image_quality" title="Wikipedia:How to improve image quality">How to improve image quality</a></li> <li><a href="/wiki/Wikipedia:Graphics_Lab/Resources" title="Wikipedia:Graphics Lab/Resources">Graphics Lab resources</a></li></ul></li> <li><a href="/wiki/Help:Sound_file_markup" title="Help:Sound file markup">Sound file markup</a></li> <li><a href="/wiki/Help:Visual_file_markup" title="Help:Visual file markup">Visual file markup</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Other graphics</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Family_trees" title="Help:Family trees">Family trees</a></li> <li><a href="/wiki/Wikipedia:Graphs_and_charts" title="Wikipedia:Graphs and charts">Graphs and charts</a> <ul><li><a href="/wiki/Wikipedia:How_to_create_charts_for_Wikipedia_articles" title="Wikipedia:How to create charts for Wikipedia articles">How to create</a></li> <li><a href="/wiki/Help:Barchart" title="Help:Barchart">Barcharts</a></li> <li><a href="/wiki/Wikipedia:To_scale_charts" title="Wikipedia:To scale charts">To scale charts</a></li></ul></li> <li><a href="/wiki/Help:Displaying_a_formula" title="Help:Displaying a formula">Math formulas</a> <ul><li><a href="/wiki/Help:Displaying_a_formula#Use_of_HTML_templates" title="Help:Displaying a formula">Math symbols</a></li></ul></li> <li><a href="/wiki/Help:Score" title="Help:Score">Musical scores</a> <ul><li><a href="/wiki/Help:Musical_symbols" title="Help:Musical symbols">Musical symbols</a></li></ul></li> <li><a href="/wiki/Wikipedia:Timeline" title="Wikipedia:Timeline">Timeline</a> <ul><li><a href="/wiki/Help:EasyTimeline_syntax" title="Help:EasyTimeline syntax">EasyTimeline syntax</a></li></ul></li> <li><a href="/wiki/Help:WikiHiero_syntax" title="Help:WikiHiero syntax">WikiHiero syntax</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Help:A_quick_guide_to_templates" title="Help:A quick guide to templates">Templates</a> and<br/><a href="/wiki/Lua_(programming_language)" title="Lua (programming language)">Lua</a> modules</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Template" title="Help:Template">Templates</a></li> <li><a href="/wiki/Wikipedia:Advanced_template_coding" title="Wikipedia:Advanced template coding">Advanced template coding</a></li> <li><a href="/wiki/Wikipedia:Template_documentation" title="Wikipedia:Template documentation">Template documentation</a></li> <li><a href="/wiki/Wikipedia:Template_index" title="Wikipedia:Template index">Template index</a></li> <li><a href="/wiki/Help:Template_limits" title="Help:Template limits">Template limits</a></li> <li><a href="/wiki/Wikipedia:Template_sandbox_and_test_cases" title="Wikipedia:Template sandbox and test cases">Template sandbox and test cases</a></li> <li><a href="/wiki/Wikipedia:Citation_templates" title="Wikipedia:Citation templates">Citation templates</a></li> <li><a href="/wiki/Help:Lua" title="Help:Lua">Lua help</a></li> <li><a href="/wiki/Wikipedia:Lua" title="Wikipedia:Lua">Lua project</a> <ul><li><a href="/wiki/Wikipedia:Lua/Resources" title="Wikipedia:Lua/Resources">Resources</a></li> <li><a href="/wiki/Wikipedia:Lua/To_do" title="Wikipedia:Lua/To do">To do</a></li></ul></li> <li><a href="/wiki/Help:Substitution" title="Help:Substitution">Substitution</a></li> <li><a href="/wiki/Help:Purge" title="Help:Purge">Purge</a> <ul><li><a href="/wiki/Help:Job_queue" title="Help:Job queue">Job queue</a></li></ul></li> <li><a href="/wiki/Help:Transclusion" title="Help:Transclusion">Transclusion</a> <ul><li><a href="/wiki/Help:Labeled_section_transclusion" title="Help:Labeled section transclusion">Labeled section</a></li> <li><a href="/wiki/Wikipedia:Transclusion_costs_and_benefits" title="Wikipedia:Transclusion costs and benefits">Costs and benefits</a></li></ul></li> <li><a href="/wiki/Wikipedia:Guide_to_Scribbling" title="Wikipedia:Guide to Scribbling">Guide to Scribbling</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Wikipedia:Administration#Data_structure_and_development" title="Wikipedia:Administration">Data structure</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Wikipedia:Namespace" title="Wikipedia:Namespace">Namespaces</a></li> <li><a href="/wiki/Wikipedia:What_is_an_article%3F" title="Wikipedia:What is an article?">Main/Article</a></li> <li><a href="/wiki/Help:Category" title="Help:Category">Category</a></li> <li><a href="/wiki/Wikipedia:Drafts" title="Wikipedia:Drafts">Draft</a></li> <li><a href="/wiki/Help:Files" title="Help:Files">File</a> <ul><li><a href="/wiki/Help:File_description_page" title="Help:File description page">File description page</a></li></ul></li> <li><a href="/wiki/Wikipedia:Help_namespace" title="Wikipedia:Help namespace">Help</a></li> <li><a href="/wiki/Wikipedia:Portal" title="Wikipedia:Portal">Portal</a></li> <li><a href="/wiki/Wikipedia:Project_namespace" title="Wikipedia:Project namespace">Project/Wikipedia</a></li> <li><a href="/wiki/Help:Talk_pages" title="Help:Talk pages">Talk</a> <ul><li><a href="/wiki/Help:Archiving_a_talk_page" title="Help:Archiving a talk page">Archiving</a> <ul><li><a href="/wiki/Help:Archiving_(plain_and_simple)" title="Help:Archiving (plain and simple)">Simple</a></li></ul></li></ul></li> <li><a href="/wiki/Wikipedia:Template_namespace" title="Wikipedia:Template namespace">Template</a></li> <li><a href="/wiki/Wikipedia:User_pages" title="Wikipedia:User pages">User</a> <ul><li><a href="/wiki/Wikipedia:User_page_design_guide" title="Wikipedia:User page design guide">User page design</a></li></ul></li> <li><a href="/wiki/Help:MediaWiki_namespace" title="Help:MediaWiki namespace">MediaWiki</a> <ul><li><a href="/wiki/Wikipedia:Bug_reports_and_feature_requests" title="Wikipedia:Bug reports and feature requests">Bug reports and feature requests</a></li> <li><a href="https://www.mediawiki.org/wiki/Extension:TimedMediaHandler" class="extiw" title="mw:Extension:TimedMediaHandler">TimedMediaHandler extension</a></li></ul></li> <li><a href="/wiki/Wikipedia:Lua" title="Wikipedia:Lua">Module</a></li> <li><a href="/wiki/Help:Special_page" title="Help:Special page">Special</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/HTML" title="HTML">HTML</a> and <a href="/wiki/CSS" title="CSS">CSS</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Cascading_Style_Sheets" title="Help:Cascading Style Sheets">Cascading Style Sheets</a></li> <li><a href="/wiki/Help:HTML_in_wikitext" title="Help:HTML in wikitext">HTML in wikitext</a></li> <li><a href="/wiki/Wikipedia:Catalogue_of_CSS_classes" title="Wikipedia:Catalogue of CSS classes">Catalogue of CSS classes</a></li> <li><a href="/wiki/Wikipedia:Common.js_and_common.css" title="Wikipedia:Common.js and common.css">Common.js and common.css</a></li> <li><a href="/wiki/Template:Mxt/User_CSS_for_a_monospaced_coding_font" title="Template:Mxt/User CSS for a monospaced coding font">User CSS for monospaced coding font</a></li> <li><a href="/wiki/Wikipedia:WikiProject_Microformats/classes" title="Wikipedia:WikiProject Microformats/classes">Classes in microformats</a></li> <li><a href="/wiki/Help:Markup_validation" title="Help:Markup validation">Markup validation</a></li> <li><a href="/wiki/Wikipedia:Span_tags" title="Wikipedia:Span tags">Span tags</a></li> <li><a href="/wiki/Help:Useful_styles" title="Help:Useful styles">Useful styles</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Wikipedia:Customisation" title="Wikipedia:Customisation">Customisation</a><br/>and tools</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Help:Preferences" title="Help:Preferences">Preferences</a></li> <li><a href="/wiki/Wikipedia:Gadget" title="Wikipedia:Gadget">Gadgets</a></li> <li><a href="/wiki/Wikipedia:Skin" title="Wikipedia:Skin">Skins</a></li> <li><a href="/wiki/Help:Citation_tools" title="Help:Citation tools">Citation tools</a></li> <li><a href="/wiki/Wikipedia:Cleaning_up_vandalism/Tools" title="Wikipedia:Cleaning up vandalism/Tools">Cleaning up vandalism tools</a></li> <li><a href="/wiki/Wikipedia:Customizing_watchlists" title="Wikipedia:Customizing watchlists">Customizing watchlists</a> <ul><li><a href="/wiki/Help:Hide_Pages_in_Watchlist" title="Help:Hide Pages in Watchlist">Hide pages</a></li></ul></li> <li><a href="/wiki/Wikipedia:Scripts" title="Wikipedia:Scripts">IRC Scripts</a></li> <li><a href="/wiki/Wikipedia:User_scripts" title="Wikipedia:User scripts">User scripts</a> <ul><li><a href="/wiki/Wikipedia:User_scripts/Guide" title="Wikipedia:User scripts/Guide">Guide</a></li> <li><a href="/wiki/Wikipedia:User_scripts/List" title="Wikipedia:User scripts/List">List</a></li> <li><a href="/wiki/Wikipedia:User_scripts/Techniques" title="Wikipedia:User scripts/Techniques">Techniques</a></li></ul></li> <li><a href="/wiki/Help:User_style" title="Help:User style">User style</a></li> <li><a href="/wiki/Wikipedia:Tools" title="Wikipedia:Tools">Tools</a> <ul><li><a href="/wiki/Wikipedia:Tools/Alternative_browsing" title="Wikipedia:Tools/Alternative browsing">Alternative browsing</a></li> <li><a href="/wiki/Wikipedia:Tools/Browser_tools" title="Wikipedia:Tools/Browser tools">Browser tools</a></li> <li><a href="/wiki/Wikipedia:Tools/Editing_tools" title="Wikipedia:Tools/Editing tools">Editing tools</a></li> <li><a href="/wiki/Wikipedia:Tools/Navigation_shortcuts" title="Wikipedia:Tools/Navigation shortcuts">Navigation shortcuts</a></li> <li><a href="/wiki/Wikipedia:Tools/Optimum_tool_set" title="Wikipedia:Tools/Optimum tool set">Optimum tool set</a></li></ul></li> <li><a href="/wiki/Wikipedia:Wikimedia_Cloud_Services" title="Wikipedia:Wikimedia Cloud Services">Wikimedia Cloud Services</a></li> <li><a href="https://www.mediawiki.org/wiki/Beta_Features" class="extiw" title="mw:Beta Features">Beta Features at MediaWiki</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Automated editing</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Wikipedia:WikiProject_Articles_for_creation/Helper_script" title="Wikipedia:WikiProject Articles for creation/Helper script">AfC helper script</a></li> <li><a href="/wiki/Wikipedia:AntiVandal" title="Wikipedia:AntiVandal">AntiVandal</a></li> <li><a href="/wiki/Wikipedia:AutoWikiBrowser" title="Wikipedia:AutoWikiBrowser">AutoWikiBrowser</a></li> <li><a href="/wiki/Wikipedia:Bots" title="Wikipedia:Bots">Bots</a> <ul><li><a href="/wiki/Help:Creating_a_bot" title="Help:Creating a bot">Creating</a></li> <li><a href="/wiki/Wikipedia:History_of_Wikipedia_bots" title="Wikipedia:History of Wikipedia bots">history</a></li></ul></li> <li><a href="/wiki/Wikipedia:HotCat" title="Wikipedia:HotCat">HotCat</a></li> <li><a href="/wiki/Wikipedia:Huggle" title="Wikipedia:Huggle">Huggle</a></li> <li><a href="/wiki/Wikipedia:Tools/Navigation_popups" title="Wikipedia:Tools/Navigation popups">Navigation popups</a></li> <li><a href="/wiki/Wikipedia:RedWarn" title="Wikipedia:RedWarn">RedWarn</a></li> <li><a href="/wiki/Wikipedia:Twinkle" title="Wikipedia:Twinkle">Twinkle</a></li> <li><a href="/wiki/Wikipedia:Ultraviolet" title="Wikipedia:Ultraviolet">Ultraviolet</a></li> <li><a href="/wiki/Wikipedia:WPCleaner" title="Wikipedia:WPCleaner">WPCleaner</a></li> <li>Inactive <ul><li><a href="/wiki/Wikipedia:Igloo" title="Wikipedia:Igloo">igloo</a></li> <li><a href="/wiki/Wikipedia:STiki" title="Wikipedia:STiki">STiki</a></li></ul></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="text-align: center;"><div> <ul><li>See also: <b><a href="/wiki/Category:Wikipedia_how-to" title="Category:Wikipedia how-to">Category:Wikipedia how-to</a></b></li> <li><b><a href="/wiki/Category:Wikipedia_information_pages" title="Category:Wikipedia information pages">Category:Wikipedia information pages</a></b><br/>Further navigation at: <a href="/wiki/Template:Wikipedia_help_pages" title="Template:Wikipedia help pages">Help pages</a> <ul><li><a href="/wiki/Template:Administrators%27_guide" title="Template:Administrators' guide">Administrators</a></li></ul></li> <li><a href="/wiki/Wikipedia:WikiProject_Accessibility/Navigation_menu" title="Wikipedia:WikiProject Accessibility/Navigation menu">Accessibility</a></li> <li><a href="/wiki/Template:Wikipedia_accounts" title="Template:Wikipedia accounts">Accounts</a></li> <li><a href="/wiki/Template:Botnav" title="Template:Botnav">Bots</a></li> <li><a href="/wiki/Template:Wikipedia_referencing" title="Template:Wikipedia referencing">Referencing</a> <ul><li><a href="/wiki/Template:Citation_metadata_navbox" title="Template:Citation metadata navbox">Citation metadata</a></li></ul></li> <li><a href="/wiki/Template:Wikipedia_templates" title="Template:Wikipedia templates">Templates</a></li> <li><a href="/wiki/Wikipedia:User_scripts/Navbox" title="Wikipedia:User scripts/Navbox">User scripts</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Help:Conditional_expressions&oldid=1256674841">https://en.wikipedia.org/w/index.php?title=Help:Conditional_expressions&oldid=1256674841</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Wikipedia_how-to" title="Category:Wikipedia how-to">Wikipedia how-to</a></li><li><a href="/wiki/Category:MediaWiki_Help" title="Category:MediaWiki Help">MediaWiki Help</a></li><li><a href="/wiki/Category:Wikipedia_template_help" title="Category:Wikipedia template help">Wikipedia template help</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden category: <ul><li><a href="/wiki/Category:ParserFunction_errors" title="Category:ParserFunction errors">ParserFunction errors</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 11 November 2024, at 01:50<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Help:Conditional_expressions&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-h7pn7","wgBackendResponseTime":158,"wgDiscussionToolsPageThreads":[{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Summary","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#if","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#ifeq","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#switch","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#expr","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#ifexpr","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#iferror","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Using_#ifexist","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Checking_for_template_parameters","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-Variadic_templates","replies":[]},{"headingLevel":2,"name":"h-","type":"heading","level":0,"id":"h-See_also","replies":[]}],"wgPageParseReport":{"discussiontools":{"limitreport-timeusage":"0.047"},"limitreport":{"cputime":"0.339","walltime":"0.413","ppvisitednodes":{"value":1165,"limit":1000000},"postexpandincludesize":{"value":39900,"limit":2097152},"templateargumentsize":{"value":1351,"limit":2097152},"expansiondepth":{"value":10,"limit":100},"expensivefunctioncount":{"value":30,"limit":500},"unstrip-depth":{"value":0,"limit":20},"unstrip-size":{"value":31805,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 264.749 1 -total"," 40.36% 106.860 1 Template:Wikipedia_technical_help"," 25.24% 66.824 1 Template:Wikipedia_how-to"," 22.11% 58.547 2 Template:Ombox"," 13.72% 36.322 2 Template:Shortcut"," 13.10% 34.682 1 Template:For"," 5.80% 15.348 5 Template:Color"," 4.55% 12.033 5 Template:Ifsubst"," 3.46% 9.152 1 Template:Namespace_detect"," 3.25% 8.609 2 Template:Ml"]},"scribunto":{"limitreport-timeusage":{"value":"0.143","limit":"10.000"},"limitreport-memusage":{"value":1876817,"limit":52428800}},"cachereport":{"origin":"mw-api-int.codfw.main-746bf6896b-xrmtc","timestamp":"20241119005208","ttl":2592000,"transientcontent":false}}});});</script> </body> </html>