1. $v = array('vv','bb'); 
2. $str = "vv,cc,abcde,m.survivalescaperooms.com,vv"; 
3. $str=preg_replace("/$v[0]/","<a href=".$v[1]." target=_blank >".$v[0]."</a>",$str,1); 
4. echo $str; 
5. //bb,cc,abcde,m.survivalescaperooms.com,vv 
6. $str=preg_replace("/$v[0]/","<a href=".$v[1]." target=_blank >".$v[0]."</a>",$str,2); 
7. //bb,cc,abcde,m.survivalescaperooms.com,bb