3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = array("blue", "red", "green", "blue", "blue"); print_r(array_keys($array, "blue"));
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 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 - 8.3.26, 8.4.1 - 8.4.13
Array ( [0] => 0 [1] => 3 [2] => 4 )
preferences:
124.46 ms | 408 KiB | 5 Q