3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [0, 1, 2]; $ref =& $array; // Necessary to trigger the old behavior $i = 0; foreach ($array as $k => &$val) { $i++; echo $val . ' '; if($i < 5 && !isset($array[$i])) $array[$i] = $val+1; if($i == 2) array_unshift($array, 'X'); } echo PHP_EOL . json_encode($array);
Output for 7.0.0 - 7.0.20, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
0 1 2 ["X",0,1,2]
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28
0 1 X 0 1 2 1 ["X",0,1,2,1]
preferences:
186.83 ms | 402 KiB | 283 Q