3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a1 = array('55','something1','something2','something3' ); $a2 = array('77','something14','something25','something36' ); $a4 = array('66.6','something15','something25','something34' ); $array = [$a1, $a2, $a4]; usort($array, function($a, $b) { if ($a[0] > $b[0]) { return 1; } else { return -1; } }); print_r($array);
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.7, 7.2.29 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 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 ( [0] => 55 [1] => something1 [2] => something2 [3] => something3 ) [1] => Array ( [0] => 66.6 [1] => something15 [2] => something25 [3] => something34 ) [2] => Array ( [0] => 77 [1] => something14 [2] => something25 [3] => something36 ) )

preferences:
107.64 ms | 409 KiB | 5 Q