3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [ ['foo' => 'a', 'bar' => 1], ['foo' => 'b', 'bar' => 2], ]; foreach ($array as $x => ['new' => &$x]); var_export($array);
Output for 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 ( 0 => array ( 'foo' => 'a', 'bar' => 1, 'new' => 0, ), 1 => array ( 'foo' => 'b', 'bar' => 2, 'new' => 1, ), )
preferences:
61.87 ms | 406 KiB | 5 Q