function.is-a.html
来自「php的帮助文档,涉及到PHP的案例和基本语法,以及实际应用内容」· HTML 代码 · 共 129 行
HTML
129 行
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Checks if the object is of this class or has this class as one of its parents</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.interface-exists.html">interface_exists</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.is-subclass-of.html">is_subclass_of</a></div> <div class="up"><a href="ref.classobj.html">Classes/Object Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.is-a" class="refentry"> <div class="refnamediv"> <h1 class="refname">is_a</h1> <p class="verinfo">(PHP 4 >= 4.2.0, PHP 5)</p><p class="refpurpose"><span class="refname">is_a</span> — <span class="dc-title">Checks if the object is of this class or has this class as one of its parents</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>is_a</b></b></span> ( <span class="methodparam"><span class="type">object</span> <tt class="parameter">$object</tt></span> , <span class="methodparam"><span class="type">string</span> <tt class="parameter">$class_name</tt></span> )</div> <p class="para rdfs-comment"> Checks if the given <i><tt class="parameter">object</tt></i> is of this class or has this class as one of its parents. </p> <blockquote><p><b class="note">Note</b>: The <b>is_a()</b> function is deprecated as of PHP 5 in favor of the <a href="language.operators.type.html" class="link">instanceof</a> type operator. <br /> </p></blockquote> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">object</tt></i></span> <dd> <p class="para"> The tested object </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">class_name</tt></i></span> <dd> <p class="para"> The class name </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> if the object is of this class or has this class as one of its parents, <b><tt>FALSE</tt></b> otherwise. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>is_a()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// define a class<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">WidgetFactory<br /></span><span style="color: #007700">{<br /> var </span><span style="color: #0000BB">$oink </span><span style="color: #007700">= </span><span style="color: #DD0000">'moo'</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #FF8000">// create a new object<br /></span><span style="color: #0000BB">$WF </span><span style="color: #007700">= new </span><span style="color: #0000BB">WidgetFactory</span><span style="color: #007700">();<br /><br />if (</span><span style="color: #0000BB">is_a</span><span style="color: #007700">(</span><span style="color: #0000BB">$WF</span><span style="color: #007700">, </span><span style="color: #DD0000">'WidgetFactory'</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"yes, \$WF is still a WidgetFactory\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> <div class="example"> <p><b>Example #2 Using the <em class="emphasis">instanceof</em> operator in PHP 5</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">$WF </span><span style="color: #007700">instanceof </span><span style="color: #0000BB">WidgetFactory</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">'Yes, $WF is a WidgetFactory'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.get-class.html" class="function" rel="rdfs-seeAlso">get_class()</a></li> <li class="member"><a href="function.get-parent-class.html" class="function" rel="rdfs-seeAlso">get_parent_class()</a></li> <li class="member"><a href="function.is-subclass-of.html" class="function" rel="rdfs-seeAlso">is_subclass_of()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.interface-exists.html">interface_exists</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.is-subclass-of.html">is_subclass_of</a></div> <div class="up"><a href="ref.classobj.html">Classes/Object Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?