3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 'hello, [how]. please don\'t remove [are] you?'; echo preg_replace('#\s*\[.+\]\s*#', ' ', $a); echo preg_replace('~\h*\[(?>[^][]++|(?R))*+]\h*~', ' ', $a);

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36.84 ms | 402 KiB | 5 Q