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200 lines
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HTML
200 lines
9.9 KiB
HTML
<!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>转换指定字符</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.strtr" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">strtr</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strtr</span> — <span class="dc-title">转换指定字符</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.strtr-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>strtr</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
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, <span class="methodparam"><span class="type">string</span> <code class="parameter">$from</code></span>
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, <span class="methodparam"><span class="type">string</span> <code class="parameter">$to</code></span>
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) : <span class="type">string</span></div>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>strtr</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
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, <span class="methodparam"><span class="type">array</span> <code class="parameter">$replace_pairs</code></span>
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) : <span class="type">string</span></div>
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<p class="para rdfs-comment">
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该函数返回 <code class="parameter">str</code> 的一个副本，并将在 <code class="parameter">from</code> 中指定的字符转换为 <code class="parameter">to</code> 中相应的字符。
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比如， <em>$from[$n]</em>中每次的出现都会被替换为
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<em>$to[$n]</em>，其中 <em>$n</em> 是两个参数都有效的位移(offset)。
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</p>
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<p class="para">
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如果 <code class="parameter">from</code> 与 <code class="parameter">to</code> 长度不相等，那么多余的字符部分将被忽略。 <code class="parameter">str</code> 的长度将会和返回的值一样。
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</p>
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<p class="para">
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If given two arguments, the second should be an <span class="type"><a href="language.types.array.html" class="type array">array</a></span> in the
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form <em>array('from' => 'to', ...)</em>. The return value is
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a <span class="type"><a href="language.types.string.html" class="type string">string</a></span> where all the occurrences of the array keys have been
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replaced by the corresponding values. The longest keys will be tried first.
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Once a substring has been replaced, its new value will not be searched
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again.
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</p>
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<p class="para">
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In this case, the keys and the values may have any length, provided that
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there is no empty key; additionally, the length of the return value may
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differ from that of <code class="parameter">str</code>.
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However, this function will be the most efficient when all the keys have the
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same size.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.strtr-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">str</code></dt>
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<dd>
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<p class="para">
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待转换的<span class="type"><span class="type 字符串">字符串</span></span>。
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</p>
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</dd>
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<dt>
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<code class="parameter">from</code></dt>
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<dd>
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<p class="para">
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<span class="type"><span class="type 字符串">字符串</span></span>中与将要被转换的目的字符 <code class="parameter">to</code> 相对应的源字符。
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</p>
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</dd>
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<dt>
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<code class="parameter">to</code></dt>
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<dd>
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<p class="para">
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<span class="type"><span class="type 字符串">字符串</span></span>中与将要被转换的字符 <code class="parameter">from</code> 相对应的目的字符。
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</p>
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</dd>
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<dt>
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<code class="parameter">replace_pairs</code></dt>
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<dd>
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<p class="para">
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参数 <code class="parameter">replace_pairs</code> 可以用来取代 <code class="parameter">to</code> 和 <code class="parameter">from</code> 参数，因为它是以 <em>array('from' => 'to', ...)</em> 格式出现的数组。
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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.strtr-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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返回转换后的<span class="type"><span class="type 字符串">字符串</span></span>。
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</p>
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<p class="para">
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如果 <code class="parameter">replace_pairs</code> 中包含一个空<span class="type"><span class="type 字符串">字符串</span></span>（<em>""</em>）键，那么将返回 <strong><code>FALSE</code></strong>。
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If the <code class="parameter">str</code> is not a scalar
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then it is not typecasted into a string, instead a warning is raised and
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<strong><code>NULL</code></strong> is returned.
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.strtr-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-5988">
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<p><strong>Example #1 <span class="function"><strong>strtr()</strong></span> 范例</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 />$addr </span><span style="color: #007700">= </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #0000BB">$addr</span><span style="color: #007700">, </span><span style="color: #DD0000">"äåö"</span><span style="color: #007700">, </span><span style="color: #DD0000">"aao"</span><span style="color: #007700">);<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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The next example shows the behavior of <span class="function"><strong>strtr()</strong></span> when
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called with only two arguments. Note the preference of the replacements
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(<em>"h"</em> is not picked because there are longer matches)
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and how replaced text was not searched again.
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</p>
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<div class="example" id="example-5989">
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<p><strong>Example #2 使用两个参数的 <span class="function"><strong>strtr()</strong></span> 范例</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 />$trans </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"hello" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"hi"</span><span style="color: #007700">, </span><span style="color: #DD0000">"hi" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"hello"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"hi all, I said hello"</span><span style="color: #007700">, </span><span style="color: #0000BB">$trans</span><span style="color: #007700">);<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 class="example-contents"><p>以上例程会输出：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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hello all, I said hi
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</pre></div>
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</div>
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</div>
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<p class="para">
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The two modes of behavior are substantially different. With three arguments,
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<span class="function"><strong>strtr()</strong></span> will replace bytes; with two, it may replace
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longer substrings.
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</p>
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<div class="example" id="example-5990">
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<p><strong>Example #3 <span class="function"><strong>strtr()</strong></span> behavior comparison</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 /></span><span style="color: #007700">echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"baab"</span><span style="color: #007700">, </span><span style="color: #DD0000">"ab"</span><span style="color: #007700">, </span><span style="color: #DD0000">"01"</span><span style="color: #007700">),</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$trans </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"ab" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"01"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">strtr</span><span style="color: #007700">(</span><span style="color: #DD0000">"baab"</span><span style="color: #007700">, </span><span style="color: #0000BB">$trans</span><span style="color: #007700">);<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 class="example-contents"><p>以上例程会输出：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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1001
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ba01
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</pre></div>
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</div>
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</div>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.strtr-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="str_replace.html" class="function" rel="rdfs-seeAlso">str_replace()</a> - 子字符串替换</span></li>
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<li class="member"><span class="function"><a href="preg_replace.html" class="function" rel="rdfs-seeAlso">preg_replace()</a> - 执行一个正则表达式的搜索和替换</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> |