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113 lines
6.2 KiB
HTML
113 lines
6.2 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>转换字符串第一个字节为 0-255 之间的值</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.ord" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">ord</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">ord</span> — <span class="dc-title">转换字符串第一个字节为 0-255 之间的值</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.ord-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>ord</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$string</code></span>
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) : <span class="type">int</span></div>
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<p class="para rdfs-comment">
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解析 <code class="parameter">string</code> 二进制值第一个字节为 0 到 255 范围的无符号整型类型。
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</p>
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<p class="para">
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如果字符串是 ASCII、 ISO-8859、Windows 1252之类单字节编码，就等于返回该字符在字符集编码表中的位置。
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但请注意，本函数不会去检测字符串的编码，尤其是不会识别类似 UTF-8 或 UTF-16 这种多字节字符的 Unicode 代码点（code point）。
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</p>
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<p class="para">
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该函数是 <span class="function"><a href="chr.html" class="function">chr()</a></span> 的互补函数。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.ord-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">string</code></dt>
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<dd>
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<p class="para">
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一个字符。
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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.ord-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 0 - 255 的整型值。
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.ord-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-5929">
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<p><strong>Example #1 <span class="function"><strong>ord()</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 />$str </span><span style="color: #007700">= </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />if (</span><span style="color: #0000BB">ord</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">) == </span><span style="color: #0000BB">10</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"The first character of \$str is a line feed.\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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<p class="para">
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<div class="example" id="example-5930">
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<p><strong>Example #2 检查 UTF-8 字符串的每一个字节</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">declare(</span><span style="color: #0000BB">encoding</span><span style="color: #007700">=</span><span style="color: #DD0000">'UTF-8'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$str </span><span style="color: #007700">= </span><span style="color: #DD0000">"🐘"</span><span style="color: #007700">;<br />for ( </span><span style="color: #0000BB">$pos</span><span style="color: #007700">=</span><span style="color: #0000BB">0</span><span style="color: #007700">; </span><span style="color: #0000BB">$pos </span><span style="color: #007700">< </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">); </span><span style="color: #0000BB">$pos </span><span style="color: #007700">++ ) {<br /> </span><span style="color: #0000BB">$byte </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">, </span><span style="color: #0000BB">$pos</span><span style="color: #007700">);<br /> echo </span><span style="color: #DD0000">'Byte ' </span><span style="color: #007700">. </span><span style="color: #0000BB">$pos </span><span style="color: #007700">. </span><span style="color: #DD0000">' of $str has value ' </span><span style="color: #007700">. </span><span style="color: #0000BB">ord</span><span style="color: #007700">(</span><span style="color: #0000BB">$byte</span><span style="color: #007700">) . </span><span style="color: #0000BB">PHP_EOL</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 class="example-contents"><p>以上例程会输出：</p></div>
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<div class="example-contents screen"><br />
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Byte 0 of $str has value 240<br />
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Byte 1 of $str has value 159<br />
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Byte 2 of $str has value 144<br />
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Byte 3 of $str has value 152<br />
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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.ord-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="chr.html" class="function" rel="rdfs-seeAlso">chr()</a> - 返回指定的字符</span></li>
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<li class="member"><a href="http://www.asciitable.com" class="link external">» ASCII 码表</a></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> |