3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = array( 0 => array('user_id' => '1', 'email'=>'email1'), 1 => array('user_id' => '2', 'email'=>'email2'), 2 => array('user_id' => '3', 'email'=>'email3') ); //var_dump(array_flip($array));
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.12 - 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

preferences:
182.37 ms | 404 KiB | 256 Q