<?php $people = array("Peter", "Joe", "Glenn", "Cleveland"); if(in_array("Glenn",$people)){ echo "Match found"; }else{ echo "Match not found"; } ?>
<?php
$a=array("a"=>"Dog","b"=>"Cat");
if(array_key_exists("a",$a)){
echo "Key exists!";
}else{
echo "Key does not exist!";
}
?>
<?php
$a=array("a"=>"Dog","b"=>"Cat","c"=>5,"d"=>"5");
echo array_search("Dog",$a);
echo array_search("5",$a);
?>
原文：http://www.cnblogs.com/suxiaolong/p/5151675.html