为具有相同值的数组创建随机数

Question

I have this array

Array
(
[19] => Array
    (
        [nState] => -1
        [bActive] => 1
    )

[20] => Array
    (
        [nState] => -1
        [bActive] => 1
    )

[21] => Array
    (
        [nState] => -1
        [bActive] =>
    )

I want to make a random for this array but always get the same values. For example I want to get always the array with keys 12 11 13 10. I searched on web but always the values are differents. Can you help me please ? Thx in advance and sorry for my english

Answer 1

You could use this variant of shuffle:

function shuffled_seed($arr, $seed) {
    $len = count($arr);
    $shuffled = [];
    while ($len) {
        $shuffled[] = array_splice($arr, $seed % $len, 1)[0];
        $seed = floor($seed / $len);
        $len--;
    }
    return $shuffled;
}

If you provide twice the same arguments, you'll get twice the same return value. The second argument is the seed. You could for instance generate this as a random number the first time, but then remember it for any next time you need to reproduce the same array.

Example call:

$arr = [1,2,3,4,5,6,7,8,9];
$seed = rand();
$result = shuffled_seed($arr, $seed);
print_r($result);

$result = shuffled_seed($arr, $seed); // same seed
print_r($result); // same result