$search = 'ok';
$str = 'abcdefokaeofff';
if(preg_match("/$search/",$str))
{echo 'yes';}
else{    echo 'no';}
 
 
in_array() 函数在数组中搜索给定的值。
<?php
$people = array("Peter", "Joe", "Glenn", "Cleveland");
if (in_array("Glenn",$people))
  {
  echo "Match found";
  }
else
  {
  echo "Match not found";
  }
?>