How do I shuffle 2 arrays exactly the same?

[roark]

Hi Guys,

 

Could anyone help me with this problem?

I would like to shuffle 2 arrays the same i.e:

 

Before shuffling:

array 1: 1, 2, 3, 4, 5

array 2: a, b, c, d, e

 

After shuffling:

array 1: 2, 4, 5, 3, 1

array 2: b, d, e, c, a

 

Both arrays index order changed in the same manner.

I'm really stumped...

 

 

Thanks

[Adam]

shuffle() is random so there's no way you can repeat it. However you could implement you're own shuffle method, for example:

 

<?php

function shuffle2arrays($array1, $array2)
{
    if (count($array1) != count($array2))
    {
        return false;
    }

    $count = count($array1);
    $keys  = array_rand(range(0, ($count-1)), $count);

    $new_array1 = array();
    $new_array2 = array();

    for ($i = 0; $i < $count; $i++)
    {
        $new_array1[$i] = $array1[$keys[$i]];
        $new_array2[$i] = $array2[$keys[$i]];
    }

    return array($new_array1, $new_array2);
}

$array1 = array(1,2,3,4,5);
$array2 = array('a','b','c','d','e');

list($array1, $array2) = shuffle2arrays($array1, $array2);

print_r($array1);
print_r($array2);

?>

 

That's the only way I can think of doing it, someone else may have a much simpler solution though.

[Adam]

To make it more like shuffle() in-fact you could pass the array by reference:

 

function shuffle2arrays(&$array1, &$array2)
{
    if (count($array1) != count($array2))
    {
        return false;
    }

    $count = count($array1);
    $keys  = array_rand(range(0, ($count-1)), $count);

    $new_array1 = array();
    $new_array2 = array();

    for ($i = 0; $i < $count; $i++)
    {
        $new_array1[$i] = $array1[$keys[$i]];
        $new_array2[$i] = $array2[$keys[$i]];
    }

    $array1 = $new_array1;
    $array2 = $new_array2;

    return true;
}

 

Then you just need to call it with:

 

shuffle2arrays($some_array, $another_array);

[ktsugihara]

Alternatively, is there an issue with having a multidimensional array?

 

$foo[a][1]; ?

 

I dont know your exact implementation so I dont know if this would work...

[Daniel0]

You can do like this:

<?php
$arr1 = array(1,2,3,4,5,6);
$arr2 = array('a','b','c','d','e','f');

$shuffle = array();
for ($i = 0, $size = min(sizeof($arr1), sizeof($arr2)); $i < $size; ++$i) {
    $shuffle[] = array($arr1[$i], $arr2[$i]);
}

shuffle($shuffle);

foreach ($shuffle as $i => $v) {
    list($arr1[$i], $arr2[$i]) = $v; 
}

var_dump($arr1, $arr2);

 

Of course you need them to have equal length.

[Adam]

Alternatively, is there an issue with having a multidimensional array?

 

$foo[a][1]; ?

 

I dont know your exact implementation so I dont know if this would work...

 

It's not recursive if that's what you meant, but it'll work on any 2 single-dimension arrays with equal length. Actually I didn't consider this originally, but it'll only work properly on integer indexes - converting literal indexes to integer in the event of them.

 

I'd just go with Daniel's solution..