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55 lines
6.1 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>检测变量是否是一个标量</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.is-scalar" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">is_scalar</h1>
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<p class="verinfo">(PHP 4 >= 4.0.5, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">is_scalar</span> — <span class="dc-title">
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检测变量是否是一个标量
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</span></p>
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</div>
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<div class="refsect1 unknown-unknown-unknown-unknown-unknown-unknown-unknown-seealsv" id="refsect1-function.is-scalar-unknown-unknown-unknown-unknown-unknown-unknown-unknown-seealsv">
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<h3 class="title">描述</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>is_scalar</strong></span>
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( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$var</code></span>
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) : <span class="type">bool</span></div>
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<p class="para rdfs-comment">
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如果给出的变量参数 <code class="parameter">var</code> 是一个标量，<span class="function"><strong>is_scalar()</strong></span>
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返回 <strong><code>TRUE</code></strong>，否则返回 <strong><code>FALSE</code></strong>。
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</p>
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<p class="para">
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标量变量是指那些包含了
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<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>、<span class="type"><a href="language.types.float.html" class="type float">float</a></span>、<span class="type"><a href="language.types.string.html" class="type string">string</a></span>
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或 <span class="type"><a href="language.types.boolean.html" class="type boolean">boolean</a></span>的变量，而
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<span class="type"><a href="language.types.array.html" class="type array">array</a></span>、<span class="type"><a href="language.types.object.html" class="type object">object</a></span> 和 <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span> 则不是标量。
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<div class="informalexample">
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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">function </span><span style="color: #0000BB">show_var</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">) {<br /> if (</span><span style="color: #0000BB">is_scalar</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #0000BB">$var</span><span style="color: #007700">;<br /> } else {<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">);<br /> }<br />}<br /></span><span style="color: #0000BB">$pi </span><span style="color: #007700">= </span><span style="color: #0000BB">3.1416</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$proteins </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"hemoglobin"</span><span style="color: #007700">, </span><span style="color: #DD0000">"cytochrome c oxidase"</span><span style="color: #007700">, </span><span style="color: #DD0000">"ferredoxin"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">show_var</span><span style="color: #007700">(</span><span style="color: #0000BB">$pi</span><span style="color: #007700">);<br /></span><span style="color: #FF8000">// 打印：3.1416<br /><br /></span><span style="color: #0000BB">show_var</span><span style="color: #007700">(</span><span style="color: #0000BB">$proteins</span><span style="color: #007700">)<br /></span><span style="color: #FF8000">// 打印：<br />// array(3) {<br />// [0]=><br />// string(10) "hemoglobin"<br />// [1]=><br />// string(20) "cytochrome c oxidase"<br />// [2]=><br />// string(10) "ferredoxin"<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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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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尽管当前的 <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span> 类型是居于整数的，但
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<span class="function"><strong>is_scalar()</strong></span> 不会把它们当作是标量，因为资源是抽象数据类型。不能依赖于执行细节，因为它可能会改变。
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</p>
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</p></blockquote>
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<p class="para">
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参见 <span class="function"><a href="is_bool.html" class="function">is_bool()</a></span>、<span class="function"><a href="is_numeric.html" class="function">is_numeric()</a></span>、<span class="function"><a href="is_float.html" class="function">is_float()</a></span>、<span class="function"><a href="is_int.html" class="function">is_int()</a></span>、<span class="function"><a href="is_real.html" class="function">is_real()</a></span>、<span class="function"><a href="is_string.html" class="function">is_string()</a></span>、<span class="function"><a href="is_object.html" class="function">is_object()</a></span>、<span class="function"><a href="is_array.html" class="function">is_array()</a></span>
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和 <span class="function"><a href="is_integer.html" class="function">is_integer()</a></span>。
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</p>
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</div>
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</div></div></div></body></html> |