3v4l.org

run code in 300+ PHP versions simultaneously
<?php $old_arr=array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20); $size = count($old_arr); print_r($size); for($i=0;$i<=19;$i++){ if ($i<=4){ $a[] = $old_arr[$i]; }elseif ($i>4 && $i<=9){ $b[] = $old_arr[$i]; }elseif ($i>9 && $i<=14){ $c[] = $old_arr[$i]; }elseif ($i>14){ $d[] = $old_arr[$i]; } } print_r($a); print_r($b); print_r($c); print_r($d); $group_order[] = mt_rand(1,4); while(count($group_order)<4){ $x=mt_rand(1,4); if(in_array($group_order,$x) == false){ $group_order[] = $x; } } print_r($group_order); ?>

preferences:
31.8 ms | 402 KiB | 5 Q