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diff --git a/files/zh-cn/web/javascript/reference/global_objects/string/split/index.html b/files/zh-cn/web/javascript/reference/global_objects/string/split/index.html new file mode 100644 index 0000000000..c1dee44c87 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/string/split/index.html @@ -0,0 +1,213 @@ +--- +title: String.prototype.split() +slug: Web/JavaScript/Reference/Global_Objects/String/split +tags: + - JavaScript + - Method + - Prototype + - Reference + - Regular Expressions + - String +translation_of: Web/JavaScript/Reference/Global_Objects/String/split +--- +<p>{{JSRef}}</p> + +<p><code><strong>split() </strong></code>方法使用指定的分隔符字符串将一个{{jsxref("String")}}对象分割成子字符串数组，以一个指定的分割字串来决定每个拆分的位置。 </p> + +<div>{{EmbedInteractiveExample("pages/js/string-split.html")}}</div> + + + +<h2 id="Syntax" name="Syntax">语法</h2> + +<pre class="syntaxbox"><code><em>str.split([separator[, limit]])</em></code> +</pre> + +<div class="blockIndicator warning"> +<p>注意：如果使用空字符串(“)作为分隔符，则字符串不是在每个用户感知的字符(图形素集群)之间，也不是在每个Unicode字符(代码点)之间，而是在每个UTF-16代码单元之间。这会摧毁代理对。还请参见<a href="https://stackoverflow.com/questions/4547609/how-do-you-get-a-string-to-a-character-array-in-javascript/34717402#34717402">how do you get a string to a character array in javascript</a></p> +</div> + +<h3 id="参数">参数</h3> + +<dl> + <dt><code>separator</code></dt> + <dd>指定表示每个拆分应发生的点的字符串。<code>separator</code> 可以是一个字符串或<a href="/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/RegExp" title="JavaScript/Reference/Global_Objects/RegExp">正则表达式</a>。 如果纯文本分隔符包含多个字符，则必须找到整个字符串来表示分割点。如果在str中省略或不出现分隔符，则返回的数组包含一个由整个字符串组成的元素。如果分隔符为空字符串，则将str原字符串中每个字符的数组形式返回。</dd> + <dt><code>limit</code></dt> + <dd>一个整数，限定返回的分割片段数量。当提供此参数时，split 方法会在指定分隔符的每次出现时分割该字符串，但在限制条目已放入数组时停止。如果在达到指定限制之前达到字符串的末尾，它可能仍然包含少于限制的条目。新数组中不返回剩下的文本。</dd> +</dl> + +<h3 id="返回值">返回值</h3> + +<p>返回源字符串以分隔符出现位置分隔而成的一个 {{jsxref("Array")}} </p> + +<h2 id="Description" name="Description">描述</h2> + +<p>找到分隔符后，将其从字符串中删除，并将子字符串的数组返回。如果没有找到或者省略了分隔符，则该数组包含一个由整个字符串组成的元素。如果分隔符为空字符串，则将str转换为字符数组。如果分隔符出现在字符串的开始或结尾，或两者都分开，分别以空字符串开头，结尾或两者开始和结束。因此，如果字符串仅由一个分隔符实例组成，则该数组由两个空字符串组成。</p> + +<p>如果分隔符是包含捕获括号的正则表达式，则每次分隔符匹配时，捕获括号的结果（包括任何未定义的结果）将被拼接到输出数组中。但是，并不是所有浏览器都支持此功能。</p> + +<p>{{Note("当字符串为空时，split（）返回一个包含一个空字符串的数组，而不是一个空数组，如果字符串和分隔符都是空字符串，则返回一个空数组。")}}</p> + +<h2 id="Examples" name="Examples">示例</h2> + +<h3 id="Example_Using_split" name="Example:_Using_split">使用 <code>split()</code></h3> + +<p>下例定义了一个函数：根据指定的分隔符将一个字符串分割成一个字符串数组。分隔字符串后，该函数依次输出原始字符串信息，被使用的分隔符，返回数组元素的个数，以及返回数组中所有的元素。</p> + +<pre class="brush: js">function splitString(stringToSplit, separator) { + var arrayOfStrings = stringToSplit.split(separator); + + console.log('The original string is: "' + stringToSplit + '"'); + console.log('The separator is: "' + separator + '"'); + console.log("The array has " + arrayOfStrings.length + " elements: "); + + for (var i=0; i < arrayOfStrings.length; i++) + console.log(arrayOfStrings[i] + " / "); +} + +var tempestString = "Oh brave new world that has such people in it."; +var monthString = "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec"; + +var space = " "; +var comma = ","; + +splitString(tempestString, space); +splitString(tempestString); +splitString(monthString, comma); +</pre> + +<p>上例输出下面结果：</p> + +<pre>The original string is: "Oh brave new world that has such people in it." +The separator is: " " +The array has 10 elements: Oh / brave / new / world / that / has / such / people / in / it. / + +The original string is: "Oh brave new world that has such people in it." +The separator is: "undefined" +The array has 1 elements: Oh brave new world that has such people in it. / + +The original string is: "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec" +The separator is: "," +The array has 12 elements: Jan / Feb / Mar / Apr / May / Jun / Jul / Aug / Sep / Oct / Nov / Dec / +</pre> + +<h3 id="Example_Removing_spaces_from_a_string" name="Example:_Removing_spaces_from_a_string">移出字符串中的空格</h3> + +<p>下例中，<code>split()</code> 方法会查找“0 或多个空白符接着的分号，再接着 0 或多个空白符”模式的字符串，找到后，就将空白符从字符串中移除，<code>nameList</code> 是 <code>split</code> 的返回数组。</p> + +<pre class="brush: js">var names = "Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand "; + +console.log(names); + +var re = /\s*(?:;|$)\s*/; +var nameList = names.split(re); + +console.log(nameList); +</pre> + +<p>上例输出两行，第一行输出原始字符串，第二行输出结果数组。</p> + +<pre><code>Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand +[ "Harry Trump", "Fred Barney", "Helen Rigby", "Bill Abel", "Chris Hand", "" ]</code> +</pre> + +<h3 id="Example_Returning_a_limited_number_of_splits" name="Example:_Returning_a_limited_number_of_splits">限制返回值中分割元素数量</h3> + +<p>下例中，<code>split</code> 查找字符串中的 0 或多个空格，并返回找到的前 3 个分割元素（splits）。</p> + +<pre class="brush: js">var myString = "Hello World. How are you doing?"; +var splits = myString.split(" ", 3); + +console.log(splits); +</pre> + +<p>上例输出：</p> + +<pre><code>["Hello", "World.", "How"]</code></pre> + +<h3 id="Example_Capturing_parentheses" name="Example:_Capturing_parentheses">靠正则来分割使结果中包含分隔块</h3> + +<p>如果 <code>separator</code> 包含捕获括号（capturing parentheses），则其匹配结果将会包含在返回的数组中。</p> + +<pre class="brush: js">var myString = "Hello 1 word. Sentence number 2."; +var splits = myString.split(/(\d)/); + +console.log(splits); +</pre> + +<p>上例输出：</p> + +<pre><code>[ "Hello ", "1", " word. Sentence number ", "2", "." ]</code></pre> + +<h3 id="使用一个数组来作为分隔符">使用一个数组来作为分隔符</h3> + +<pre><code>const myString = 'this|is|a|Test'; +const splits = myString.split(['|']); + +console.log(splits); //["this", "is", "a", "Test"] + +const myString = 'ca,bc,a,bca,bca,bc'; + +const splits = myString.split(['a','b']); +// myString.split(['a','b']) is same as myString.split(String(['a','b'])) + +console.log(splits); //["c", "c,", "c", "c", "c"]</code></pre> + +<h3 id="用split来颠倒字符串顺序">用split()来颠倒字符串顺序</h3> + +<div class="blockIndicator warning"> +<p>注意这并非一种很健壮的逆转字符串的方法:</p> + +<pre><code>const str = 'asdfghjkl'; +const strReverse = str.split('').reverse().join(''); // 'lkjhgfdsa' +// split() returns an array on which reverse() and join() can be applied</code></pre> + +<p>如果字符串包含图形素集群，即使使用Unicode感知的拆分(use for example <a href="https://github.com/mathiasbynens/esrever">esrever</a> instead)，也不能工作。</p> + +<pre><code>const str = 'résumé'; +const strReverse = str.split(/(?:)/u).reverse().join(''); +// => "́emuśer"</code></pre> + +<p>Bonus: use {{jsxref("Operators/Comparison_Operators", "===", "#Identity_strict_equality_(===)")}} operator to test if the original string was palindrome.</p> +</div> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>ECMAScript 3rd Edition.</td> + <td>Standard</td> + <td>Initial definition.<br> + Implemented in JavaScript 1.1</td> + </tr> + <tr> + <td>{{SpecName('ES5.1', '#sec-15.5.4.14', 'String.prototype.split')}}</td> + <td>{{Spec2('ES5.1')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ES6', '#sec-string.prototype.split', 'String.prototype.split')}}</td> + <td>{{Spec2('ES6')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<p>{{Compat("javascript.builtins.String.split")}}</p> + +<h2 id="See_also" name="See_also">相关链接</h2> + +<ul> + <li>{{jsxref("String.prototype.charAt()")}}</li> + <li>{{jsxref("String.prototype.indexOf()")}}</li> + <li>{{jsxref("String.prototype.lastIndexOf()")}}</li> + <li>{{jsxref("Array.prototype.join()")}}</li> +</ul> |