随机化数组中的一些元素

Question

Hi I have a set or array:

$arr = ['1','2','3','4','5','6','7','8','9','0'];
shuffle($arr);

this will return the randomized order of the array. but how can I code if the '3','4' and '8','9','0' must together? I mean the other value can go random order but these '3','4' and '8','9','0' must join together.

Answer 1

Another way would be to get those ordered elements first (another copy), then shuffle the original, then remerge them again with union:

$arr = ['1','2','3','4','5','6','7','8','9','0'];
$arr2 = array_filter($arr, function($e){ // get those elements you want preversed
    return in_array($e, [3, 4, 8, 9, 0]);
});
shuffle($arr); // shuffle the original
$ordered = $arr2 + $arr; // use union instead of array merge
ksort($ordered); // sort it by key

print_r($ordered);

Sample Output