打乱数组的顺序

主要思路打乱数组的key

$a = [1,2,3,4,5,6,7];
$l  = count($a);
for($i =0;$i<$l;$i++){
    $key1 = rand(0,$l);
    $key2 = rand(0,$l);
    $temp = $a[$key1];
    $a[$key1] = $a[$key2];
    $a[$key2] = $temp;
}