3v4l.org

run code in 300+ PHP versions simultaneously
<?php $msg = "1a12v21s1fs4d4"; $txt = "/(1[a-z]+1)|(4[a-z]4)/"; $res = preg_replace($txt,"$1 $2",$msg); echo $res;

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37.07 ms | 402 KiB | 5 Q