3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arrCombined = array(); $arrColors = array('R', 'B', 'G' ,'Y'); $arrNumbers = array('1', '2', '3', '4'); foreach($arrColors as $colorK => $colorV) { foreach($arrNumbers as $numK => $numV) { echo $colorV.' => '.$arrNumbers[$colorK]; echo "\n"; } }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
R => 1 R => 1 R => 1 R => 1 B => 2 B => 2 B => 2 B => 2 G => 3 G => 3 G => 3 G => 3 Y => 4 Y => 4 Y => 4 Y => 4

preferences:
257.31 ms | 406 KiB | 456 Q