3v4l.org

run code in 300+ PHP versions simultaneously
<?php $v = 'potato'; $file = ' blah blah potatos blah pomidoros blah potato blah potato bbb blue fadf uuu there is a potato too!! hah! '; echo preg_match_all("~\W{$v}\W~",$file);

preferences:
65.53 ms | 402 KiB | 5 Q