3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str = "####KELLY##### and ###ANOTHER###### not ####foo#### but: ###SHARE###MIDDLE###HASHES### ?"; echo $str . "\n"; echo preg_replace('/(?:#{3}|\G(?!^))\K[A-Z](?=[A-Z]*#{3})/', '#', $str);

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32.06 ms | 404 KiB | 5 Q