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175 lines
9.0 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>计算指定字符串在目标字符串中最后一次出现的位置</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.strrpos" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">strrpos</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strrpos</span> — <span class="dc-title">计算指定字符串在目标字符串中最后一次出现的位置</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.strrpos-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>strrpos</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$haystack</code></span>
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, <span class="methodparam"><span class="type">string</span> <code class="parameter">$needle</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$offset</code><span class="initializer"> = 0</span></span>
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] ) : <span class="type">int</span></div>
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<p class="para rdfs-comment">
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返回字符串 <code class="parameter">haystack</code> 中 <code class="parameter">needle</code> 最后一次出现的数字位置。注意 PHP4 中，needle 只能为单个字符。如果 needle 被指定为一个字符串，那么将仅使用第一个字符。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.strrpos-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">haystack</code></dt>
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<dd>
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<p class="para">
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在此字符串中进行查找。
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</p>
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</dd>
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<dt>
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<code class="parameter">needle</code></dt>
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<dd>
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<p class="para">
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如果 <code class="parameter">needle</code>不是一个字符串，它将被转换为整型并被视为字符的顺序值。
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</p>
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</dd>
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<dt>
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<code class="parameter">offset</code></dt>
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<dd>
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<p class="para">
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或许会查找字符串中任意长度的子字符串。负数值将导致查找在字符串结尾处开始的计数位置处结束。
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.strrpos-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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返回 needle 存在的位置。如果没有找到，返回 <strong><code>FALSE</code></strong>。
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Also note that string positions start at 0, and not 1.
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</p>
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<p class="para">
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Returns <strong><code>FALSE</code></strong> if the needle was not found.
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</p>
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<div class="warning"><strong class="warning">Warning</strong><p class="simpara">此函数可能返回布尔值
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<strong><code>FALSE</code></strong>，但也可能返回等同于 <strong><code>FALSE</code></strong> 的非布尔值。请阅读 <a href="language.types.boolean.html" class="link">布尔类型</a>章节以获取更多信息。应使用
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<a href="language.operators.comparison.html" class="link">===
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运算符</a>来测试此函数的返回值。</p></div>
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</div>
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<div class="refsect1 changelog" id="refsect1-function.strrpos-changelog">
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<h3 class="title">更新日志</h3>
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<p class="para">
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<table class="doctable informaltable">
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<thead>
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<tr>
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<th>版本</th>
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<th>说明</th>
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</tr>
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</thead>
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<tbody class="tbody">
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<tr>
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<td>5.0.0</td>
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<td>
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参数 <code class="parameter">needle</code> 可以是一个多字符的字符串。
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</td>
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</tr>
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<tr>
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<td>5.0.0</td>
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<td>
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引入 <code class="parameter">offset</code> 参数。
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</td>
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</tr>
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</tbody>
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</table>
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.strrpos-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-5980">
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<p><strong>Example #1 检查字串是否存在</strong></p>
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<div class="example-contents"><p>
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很容易将“在位置 0 处找到”和“未发现字符串”这两种情况搞错。这是检测区别的办法：
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</p></div>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /><br />$pos </span><span style="color: #007700">= </span><span style="color: #0000BB">strrpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$mystring</span><span style="color: #007700">, </span><span style="color: #DD0000">"b"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$pos </span><span style="color: #007700">=== </span><span style="color: #0000BB">false</span><span style="color: #007700">) { </span><span style="color: #FF8000">// 注意: 三个等号<br /> // 未发现...<br /></span><span style="color: #007700">}<br /><br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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<p class="para">
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<div class="example" id="example-5981">
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<p><strong>Example #2 使用偏移位置进行查找</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br />$foo </span><span style="color: #007700">= </span><span style="color: #DD0000">"0123456789a123456789b123456789c"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">strrpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$foo</span><span style="color: #007700">, </span><span style="color: #DD0000">'7'</span><span style="color: #007700">, -</span><span style="color: #0000BB">5</span><span style="color: #007700">)); </span><span style="color: #FF8000">// 从尾部第 5 个位置开始查找<br /> // 结果: int(17)<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">strrpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$foo</span><span style="color: #007700">, </span><span style="color: #DD0000">'7'</span><span style="color: #007700">, </span><span style="color: #0000BB">20</span><span style="color: #007700">)); </span><span style="color: #FF8000">// 从第 20 个位置开始查找<br /> // 结果: int(27)<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">strrpos</span><span style="color: #007700">(</span><span style="color: #0000BB">$foo</span><span style="color: #007700">, </span><span style="color: #DD0000">'7'</span><span style="color: #007700">, </span><span style="color: #0000BB">28</span><span style="color: #007700">)); </span><span style="color: #FF8000">// 结果: bool(false)<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.strrpos-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="strpos.html" class="function" rel="rdfs-seeAlso">strpos()</a> - 查找字符串首次出现的位置</span></li>
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<li class="member"><span class="function"><a href="stripos.html" class="function" rel="rdfs-seeAlso">stripos()</a> - 查找字符串首次出现的位置（不区分大小写）</span></li>
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<li class="member"><span class="function"><a href="strripos.html" class="function" rel="rdfs-seeAlso">strripos()</a> - 计算指定字符串在目标字符串中最后一次出现的位置（不区分大小写）</span></li>
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<li class="member"><span class="function"><a href="strrchr.html" class="function" rel="rdfs-seeAlso">strrchr()</a> - 查找指定字符在字符串中的最后一次出现</span></li>
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<li class="member"><span class="function"><a href="substr.html" class="function" rel="rdfs-seeAlso">substr()</a> - 返回字符串的子串</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |