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129 lines
7.5 KiB
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129 lines
7.5 KiB
HTML
<article id="wikiArticle">
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<p></p><p></p>
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<p><strong><code>toString()</code></strong> 方法返回指定 <a href="Reference/Global_Objects/Number" title="JavaScript 的 Number 对象是经过封装的能让你处理数字值的对象。Number 对象由 Number() 构造器创建。"><code>Number</code></a> 对象的字符串表示形式。</p>
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<h2 id="Syntax" name="Syntax">语法</h2>
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<pre><code><var>numObj</var>.toString([<var>radix</var>])</code>
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</code></pre>
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<h3 id="Parameter" name="Parameter">参数</h3>
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<dl>
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<dt>radix</dt>
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<dd>指定要用于数字到字符串的转换的基数(从2到36)。如果未指定 <samp>radix</samp> 参数,则默认值为 10。</dd>
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</dl>
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<h3 id="异常信息">异常信息</h3>
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<dl>
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<dt><a href="Reference/Global_Objects/RangeError" title="RangeError对象标明一个错误,当一个值不在其所允许的范围或者集合中。"><code>RangeError</code></a></dt>
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<dd>
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<p>如果 <code>toString()</code> 的 radix 参数不在 2 到 36 之间,将会抛出一个 <a href="Reference/Global_Objects/RangeError" title="RangeError对象标明一个错误,当一个值不在其所允许的范围或者集合中。"><code>RangeError</code></a>。</p>
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</dd>
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</dl>
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<h2 id="Description" name="Description">描述</h2>
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<p><a href="Reference/Global_Objects/Number" title="JavaScript 的 Number 对象是经过封装的能让你处理数字值的对象。Number 对象由 Number() 构造器创建。"><code>Number</code></a> 对象覆盖了 <a href="Reference/Global_Objects/Object" title="Object 构造函数创建一个对象包装器。"><code>Object</code></a> 对象上的 <code>toString()</code> 方法,它不是继承的 <a href="Reference/Global_Objects/Object/toString" title="toString() 方法返回一个表示该对象的字符串。"><code>Object.prototype.toString()</code></a>。对于 <a href="Reference/Global_Objects/Number" title="JavaScript 的 Number 对象是经过封装的能让你处理数字值的对象。Number 对象由 Number() 构造器创建。"><code>Number</code></a> 对象,<code>toString()</code> 方法以指定的基数返回该对象的字符串表示。</p>
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<p>如果转换的基数大于10,则会使用字母来表示大于9的数字,比如基数为16的情况,则使用a到f的字母来表示10到15。</p>
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<p>如果基数没有指定,则使用 10。</p>
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<p>如果对象是负数,则会保留负号。即使radix是2时也是如此:返回的字符串包含一个负号(-)前缀和正数的二进制表示,<strong>不是</strong> 数值的二进制补码。</p>
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<p>进行数字到字符串的转换时,建议<strong>用小括号将要转换的目标括起来</strong>,防止出错。</p>
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<h2 id="Examples" name="Examples">例子</h2>
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<pre><code class="language-javascript"><code>var count = 10;
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console.log(count.toString()); // 输出 '10'
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console.log((17).toString()); // 输出 '17'
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console.log((17.2).toString()); // 输出 '17.2'
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var x = 6;
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console.log(x.toString(2)); // 输出 '110'
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console.log((254).toString(16)); // 输出 'fe'
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console.log((-10).toString(2)); // 输出 '-1010'
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console.log((-0xff).toString(2)); // 输出 '-11111111'</code>
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</code></pre>
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<h2 id="规范">规范</h2>
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<table class="standard-table">
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<tbody>
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<tr>
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<th scope="col">Specification</th>
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<th scope="col">Status</th>
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<th scope="col">Comment</th>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%201st%20edition,%20June%201997.pdf" hreflang="en" lang="en" rel="noopener" title="ECMAScript 1st Edition (ECMA-262)">ECMAScript 1st Edition (ECMA-262)</a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td>Initial definition. Implemented in JavaScript 1.1.</td>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/5.1/#sec-15.7.4.2" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">Number.prototype.tostring</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td> </td>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-number.prototype.tostring" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Number.prototype.tostring</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td> </td>
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</tr>
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</tbody>
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</table>
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<h2 id="浏览器兼容性">浏览器兼容性</h2>
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<div><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
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This compatibility table still uses the old format,
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because we haven't yet converted the data it contains.
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<strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
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<div class="htab">
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<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
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<ul>
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<li class="selected"><a>Desktop</a></li>
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<li><a>Mobile</a></li>
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</ul>
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</div></div>
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<div id="compat-desktop">
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<table class="compat-table">
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<tbody>
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<tr>
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<th>Feature</th>
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<th>Chrome</th>
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<th>Firefox (Gecko)</th>
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<th>Internet Explorer</th>
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<th>Opera</th>
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<th>Safari</th>
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</tr>
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<tr>
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<td>Basic support</td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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</tr>
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</tbody>
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</table>
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</div>
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<div id="compat-mobile">
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<table class="compat-table">
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<tbody>
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<tr>
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<th>Feature</th>
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<th>Android</th>
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<th>Chrome for Android</th>
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<th>Firefox Mobile (Gecko)</th>
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<th>IE Mobile</th>
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<th>Opera Mobile</th>
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<th>Safari Mobile</th>
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</tr>
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<tr>
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<td>Basic support</td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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</tr>
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</tbody>
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</table>
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</div>
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<h2 id="相关链接">相关链接</h2>
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<ul>
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<li><a href="Reference/Global_Objects/Number/toFixed" title="toFixed() 方法使用定点表示法来格式化一个数。"><code>Number.prototype.toFixed()</code></a></li>
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<li><a href="Reference/Global_Objects/Number/toExponential" title="toExponential() 方法以指数表示法返回该数值字符串表示形式。"><code>Number.prototype.toExponential()</code></a></li>
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<li><a href="Reference/Global_Objects/Number/toPrecision" title="toPrecision() 方法以指定的精度返回该数值对象的字符串表示。"><code>Number.prototype.toPrecision()</code></a></li>
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</ul>
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</article> |