3v4l.org

run code in 300+ PHP versions simultaneously
<?php $values = array( 'foo' => 10, 'bar' => 20, 'baz' => 30 ); $newarray = array(); foreach($values as $k => $v) { $newarray[$k] = $v; if($k == 'bar') $newarray['qux'] = 21; } echo json_encode($newarray);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 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 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
{"foo":10,"bar":20,"qux":21,"baz":30}

preferences:
192.08 ms | 403 KiB | 287 Q