3v4l.org

run code in 500+ PHP versions simultaneously
<?php $regex = '#([a-zA-z ])\1{2,}$#'; $string = 'rrrr'; preg_match($regex, $string, $matches); var_dump($matches);
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.6 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array(2) { [0]=> string(4) "rrrr" [1]=> string(1) "r" }

preferences:
96.95 ms | 1447 KiB | 4 Q