CINXE.COM
replaceFirstMapped method - String class - dart:core library - Dart API
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, height=device-height, initial-scale=1, user-scalable=no"> <meta name="description" content="API docs for the replaceFirstMapped method from the String class, for the Dart programming language."> <title>replaceFirstMapped method - String class - dart:core library - Dart API</title> <link rel="canonical" href="https://api.dart.dev/dart-core/String/replaceFirstMapped.html"> <link rel="preconnect" href="https://fonts.gstatic.com"> <link href="https://fonts.googleapis.com/css2?family=Roboto+Mono:ital,wght@0,300;0,400;0,500;0,700;1,400&display=swap" rel="stylesheet"> <link href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@24,400,0,0" rel="stylesheet"> <link rel="stylesheet" href="../../static-assets/github.css?v1"> <link rel="stylesheet" href="../../static-assets/styles.css?v1"> <link rel="icon" href="../../static-assets/favicon.png?v1"> <!-- Google tag (gtag.js) --> <script async src="https://www.googletagmanager.com/gtag/js?id=G-VVQ8908SJ5"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-VVQ8908SJ5'); </script> <link rel="preconnect" href="https://fonts.googleapis.com"> <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin> <link rel="preload" href="https://fonts.googleapis.com/css2?family=Google+Sans+Text:wght@400&family=Google+Sans:wght@500&display=swap" as="style"> <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Google+Sans+Text:wght@400&family=Google+Sans:wght@500&display=swap"> <link rel="stylesheet" href="https://www.gstatic.com/glue/cookienotificationbar/cookienotificationbar.min.css"> </head> <body data-base-href="../../" data-using-base-href="false" class="light-theme"> <div id="overlay-under-drawer"></div> <header id="title"> <span id="sidenav-left-toggle" class="material-symbols-outlined" role="button" tabindex="0">menu</span> <ol class="breadcrumbs gt-separated dark hidden-xs"> <li><a href="../../index.html">Dart</a></li> <li><a href="../../dart-core/dart-core-library.html">dart:core</a></li> <li><a href="../../dart-core/String-class.html">String</a></li> <li class="self-crumb">replaceFirstMapped abstract method</li> </ol> <div class="self-name">replaceFirstMapped</div> <form class="search navbar-right" role="search"> <input type="text" id="search-box" autocomplete="off" disabled class="form-control typeahead" placeholder="Loading search..."> </form> <div class="toggle" id="theme-button" title="Toggle brightness"> <label for="theme"> <input type="checkbox" id="theme" value="light-theme"> <span id="dark-theme-button" class="material-symbols-outlined"> dark_mode </span> <span id="light-theme-button" class="material-symbols-outlined"> light_mode </span> </label> </div> </header> <main> <div id="dartdoc-main-content" class="main-content" data-above-sidebar="dart-core/String-class-sidebar.html" data-below-sidebar=""> <div> <div id="external-links" class="btn-group"><a title="View source code" class="source-link" href="https://github.com/dart-lang/sdk/blob/88c9758ef131d430d8ce595c6bfb4c90574d3ddd/sdk/lib/core/string.dart#L525"><span class="material-symbols-outlined">description</span></a></div> <h1><span class="kind-method">replaceFirstMapped</span> abstract method </h1></div> <section class="multi-line-signature"> <span class="returntype"><a href="../../dart-core/String-class.html">String</a></span> <span class="name ">replaceFirstMapped</span>(<wbr><ol class="parameter-list single-line"> <li><span class="parameter" id="replaceFirstMapped-param-from"><span class="type-annotation"><a href="../../dart-core/Pattern-class.html">Pattern</a></span> <span class="parameter-name">from</span>, </span></li> <li><span class="parameter" id="replaceFirstMapped-param-replace"><span class="type-annotation"><a href="../../dart-core/String-class.html">String</a></span> <span class="parameter-name">replace</span>(<ol class="parameter-list single-line"> <li><span class="parameter" id="replace-param-match"><span class="type-annotation"><a href="../../dart-core/Match-class.html">Match</a></span> <span class="parameter-name">match</span></span></li> </ol>), [</span></li> <li><span class="parameter" id="replaceFirstMapped-param-startIndex"><span class="type-annotation"><a href="../../dart-core/int-class.html">int</a></span> <span class="parameter-name">startIndex</span> = <span class="default-value">0</span></span></li> </ol>]) </section> <section class="desc markdown"> <p>Replace the first occurrence of <code>from</code> in this string.</p> <pre class="language-dart"><code class="language-dart">const string = 'Dart is fun'; print(string.replaceFirstMapped( 'fun', (m) => 'open source')); // Dart is open source print(string.replaceFirstMapped( RegExp(r'\w(\w*)'), (m) => '<${m[0]}-${m[1]}>')); // <Dart-art> is fun </code></pre> <p>Returns a new string, which is this string except that the first match of <code>from</code>, starting from <code>startIndex</code>, is replaced by the result of calling <code>replace</code> with the match object.</p> <p>The <code>startIndex</code> must be non-negative and no greater than <a href="../../dart-core/String/length.html">length</a>.</p> </section> <section class="summary source-code" id="source"> <h2><span>Implementation</span></h2> <pre class="language-dart"><code class="language-dart">String replaceFirstMapped(Pattern from, String replace(Match match), [int startIndex = 0]);</code></pre> </section> </div> <!-- /.main-content --> <div id="dartdoc-sidebar-left" class="sidebar sidebar-offcanvas-left"> <!-- The search input and breadcrumbs below are only responsively visible at low resolutions. --> <header id="header-search-sidebar" class="hidden-l"> <form class="search-sidebar" role="search"> <input type="text" id="search-sidebar" autocomplete="off" disabled class="form-control typeahead" placeholder="Loading search..."> </form> </header> <ol class="breadcrumbs gt-separated dark hidden-l" id="sidebar-nav"> <li><a href="../../index.html">Dart</a></li> <li><a href="../../dart-core/dart-core-library.html">dart:core</a></li> <li><a href="../../dart-core/String-class.html">String</a></li> <li class="self-crumb">replaceFirstMapped abstract method</li> </ol> <h5>String class</h5> <div id="dartdoc-sidebar-left-content"></div> </div><!--/.sidebar-offcanvas--> <div id="dartdoc-sidebar-right" class="sidebar sidebar-offcanvas-right"> </div><!--/.sidebar-offcanvas--> </main> <footer> <span class="no-break"> Dart 3.5.4 </span> <span class="glue-footer"> <span class="no-break"> | <a href="https://dart.dev/terms" title="Terms of use">Terms</a> </span> <span class="no-break"> | <a href="https://policies.google.com/privacy" target="_blank" rel="noopener" title="Privacy policy" class="no-automatic-external">Privacy</a> </span> <span class="no-break"> | <a href="https://dart.dev/security" title="Security philosophy and practices">Security</a> </span> <div class="copyright" style="font-size: 0.9em; color: darkgrey; margin-top: 0.5em;"> Except as otherwise noted, this site is licensed under a <a style="color: darkgrey;" href="https://creativecommons.org/licenses/by/4.0/"> Creative Commons Attribution 4.0 International License</a> and code samples are licensed under the <a style="color: darkgrey;" href="https://opensource.org/licenses/BSD-3-Clause" class="no-automatic-external"> 3-Clause BSD License</a> </div> </span> </footer> <script src="../../static-assets/highlight.pack.js?v1"></script> <script src="../../static-assets/docs.dart.js"></script> <button aria-hidden="true" class="glue-footer__link glue-cookie-notification-bar-control"> Cookies management controls </button> <script src="https://www.gstatic.com/glue/cookienotificationbar/cookienotificationbar.min.js" data-glue-cookie-notification-bar-category="2B"> </script> </body> </html>