3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = [ 5 => 'b', 10 => 'c', ]; var_export($arr); echo PHP_EOL; array_unshift($arr, 'a'); var_export($arr); echo PHP_EOL;
Output for 5.6.0 - 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.29, 8.2.0 - 8.2.23, 8.3.0 - 8.3.11
array ( 5 => 'b', 10 => 'c', ) array ( 0 => 'a', 1 => 'b', 2 => 'c', )
preferences:
47.27 ms | 407 KiB | 5 Q