3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = array(1 => 'A', 2 => 'B', '3' => 'C'); foreach($arr as $key => $value) { echo $key; }
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.6 - 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
123

preferences:
164.37 ms | 403 KiB | 197 Q