uTools-Manuals/docs/php/strspn.html
2019-04-08 23:22:26 +08:00

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<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>计算字符串中全部字符都存在于指定字符集合中的第一段子串的长度。</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.strspn" class="refentry">
<div class="refnamediv">
<h1 class="refname">strspn</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strspn</span> &mdash; <span class="dc-title">
计算字符串中全部字符都存在于指定字符集合中的第一段子串的长度。
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.strspn-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>strspn</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$subject</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$mask</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$start</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
]] ) : <span class="type">int</span></div>
<p class="para rdfs-comment">
返回 <code class="parameter">subject</code> 中全部字符<em class="emphasis"></em>存在于 <code class="parameter">mask</code> 中的第一组连续字符(子字符串)的长度。
</p>
<p class="para">
如果省略了 <code class="parameter">start</code><code class="parameter">length</code> 参数,则检查整个 <code class="parameter">subject</code> 字符串;如果指定了这两个参数,则效果等同于调用 <em>strspn(substr($subject, $start, $length), $mask)</em>(更多信息,参见 <a href="substr.html" class="xref">substr</a> )。
</p>
<p class="para">
代码行:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$var&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">strspn</span><span style="color: #007700">(</span><span style="color: #DD0000">"42&nbsp;is&nbsp;the&nbsp;answer&nbsp;to&nbsp;the&nbsp;128th&nbsp;question."</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"1234567890"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
</div>
<var class="varname"><var class="varname">$var</var></var> 将被指派为 2因为 &#039;42&#039;<code class="parameter">subject</code> 中第一段全部字符都存在于 &#039;1234567890&#039; 的连续字符。
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.strspn-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">subject</code></dt>
<dd>
<p class="para">
待检查的字符串。
</p>
</dd>
<dt>
<code class="parameter">mask</code></dt>
<dd>
<p class="para">
检查字符列表。
</p>
</dd>
<dt>
<code class="parameter">start</code></dt>
<dd>
<p class="para">
<code class="parameter">subject</code> 的开始检查位置。
</p>
<p class="para">
如果 <code class="parameter">start</code> 被设置并且是非负的,<span class="function"><strong>strspn()</strong></span> 将从 <code class="parameter">subject</code> 的第 <code class="parameter">start</code> 个位置开始检查。例如,在字符串 &#039;<em>abcdef</em>&#039; 中,第 <em>0</em> 个位置的字符是 &#039;<em>a</em>&#039;,第二个位置的字符是 &#039;<em>c</em>&#039;,等等。
</p>
<p class="para">
如果 <code class="parameter">start</code> 被设置并且为负数,<span class="function"><strong>strspn()</strong></span> 将从 <code class="parameter">subject</code> 的尾部倒数第 <code class="parameter">start</code> 个位置开始检查 <code class="parameter">subject</code>
</p>
</dd>
<dt>
<code class="parameter">length</code></dt>
<dd>
<p class="para">
<code class="parameter">subject</code> 中检查的长度。
</p>
<p class="para">
如果 <code class="parameter">length</code> 被设置并且为非负数,那么将从起始位置开始,检查 <code class="parameter">subject</code><code class="parameter">length</code> 个长度的字符。
</p>
<p class="para">
如果 <code class="parameter">length</code> 被设置并且为负数,那么将从起始位置开始,直到从 <code class="parameter">subject</code> 尾部开始第 <code class="parameter">length</code> 个位置,对 <code class="parameter">subject</code> 进行检查。
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.strspn-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
返回 <code class="parameter">str1</code> 中第一段全部字符都存在于 <code class="parameter">str2</code> 范围的字符串的长度。
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.strspn-changelog">
<h3 class="title">更新日志</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>版本</th>
<th>说明</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>4.3.0</td>
<td>
新增 <code class="parameter">start</code><code class="parameter">length</code> 参数。
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.strspn-examples">
<h3 class="title">范例</h3>
<p class="para">
<div class="example" id="example-5982">
<p><strong>Example #1 <span class="function"><strong>strspn()</strong></span> 范例</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">strspn</span><span style="color: #007700">(</span><span style="color: #DD0000">"foo"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"o"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;打印:&nbsp;2<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>以上例程会输出:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
int(0)
int(2)
int(1)
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.strspn-notes">
<h3 class="title">注释</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数可安全用于二进制对象。</span></p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.strspn-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="strcspn.html" class="function" rel="rdfs-seeAlso">strcspn()</a> - 获取不匹配遮罩的起始子字符串的长度</span></li>
</ul>
</p>
</div>
</div></div></div></body></html>