3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = array(1,2,3,3,3,4,5); var_dump(array_keys($arr,3));
Output for 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
array(3) { [0]=> int(2) [1]=> int(3) [2]=> int(4) }
preferences:
123.81 ms | 407 KiB | 5 Q