<HTML ><HEAD ><TITLE >array_key_exists</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="PHP Manual" HREF="index.html"><LINK REL="UP" TITLE="Array Functions" HREF="ref.array.html"><LINK REL="PREVIOUS" TITLE="array_intersect" HREF="function.array-intersect.html"><LINK REL="NEXT" TITLE="array_keys" HREF="function.array-keys.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=ISO-8859-1"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.array-intersect.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.array-keys.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.array-key-exists" ></A >array_key_exists</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN7561" ></A ><P > (PHP 4 >= 4.1.0)</P >array_key_exists -- Checks if the given key or index exists in the array</DIV ><DIV CLASS="refsect1" ><A NAME="AEN7564" ></A ><H2 >Description</H2 >bool <B CLASS="methodname" >array_key_exists</B > ( mixed key, array search)<BR ></BR ><P > <B CLASS="function" >array_key_exists()</B > returns <TT CLASS="constant" ><B >TRUE</B ></TT > if the given <TT CLASS="parameter" ><I >key</I ></TT > is set in the array. <TT CLASS="parameter" ><I >key</I ></TT > can be any value possible for an array index. </P ><P > <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN7581" ></A ><P ><B >Example 1. <B CLASS="function" >array_key_exists()</B > example</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="php" >$search_array = array("first" => 1, "second" => 4); if (array_key_exists("first", $search_array)) { echo "The 'first' element is in the array"; }</PRE ></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >Note: </B > The name of this function is <B CLASS="function" >key_exists()</B > in PHP version 4.0.6. </P ></BLOCKQUOTE ></DIV ><P > See also <A HREF="function.isset.html" ><B CLASS="function" >isset()</B ></A >. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.array-intersect.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.array-keys.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >array_intersect</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.array.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >array_keys</TD ></TR ></TABLE ></DIV ></BODY ></HTML >