Question

I have 2 identical arrays with integers. What I’m trying to do is shuffle both arrays so no numbers are repeating and that they don’t match up. For instance:

If Array 1 has 4 ints {1, 2, 3, 4) and Array2 has 4 ints {1, 2, 3, 4). I need them to be shuffled so the elements in Array1 don’t match the elements in Array 2.

The code I have so far:

    $Array1 = array();
    $Array2 = array();

while($row = mysql_fetch_assoc($result))
{   
    $Array1[] = $row['id'];
    $Array2[] = $row['id']; 
}
shuffle($Array1);
shuffle($Array2);
array_unique($Array1);
array_unique($Array2);
    for($i = 0; $i < sizeof($Array1); $i++)
    {
        if($Array1[$i] == $Array2[$i])
        {
            array_rand($Array1);
            array_rand($Array2);
            array_unique($Array1);
            array_unique($Array2);
        }
    }

Without the array_rand() and array_unique() in the if statement, the output is correctly shuffled with no repeating numbers in both arrays, however I still get matches. Any help?

Answer 1

$Array1 = $Array2 = array(1,2,3,4);
$Array1 = array_unique($Array1); 
$Array2 = array_unique($Array2);

if (count($Array1) == 1 && count($Array2) == 1 && $Array1 == $Array2) {
   die("Arrays can never be randomized differently");
}  

shuffle($Array1);

do {
   shuffle($Array2);
}  
while (array_intersect_assoc($Array1, $Array2));

var_dump($Array1, $Array2);