How to shuffle array in PHP

Posted on Nov 21, 2022

See how you can shuffle regular and associative arrays in PHP


To shuffle arrays in PHP, you can use the provided shuffle() function.

The shuffle() function randomizes the order of array elements that you passed as its argument:

shuffle(array &$array): bool

This function modifies the original array variable. It returns boolean true when the shuffle succeeds, otherwise it returns false.

Here’s an example of using the shuffle() array:

<?php

$arr = [1, 2, 3, 4, 5];

shuffle($arr);

print_r($arr);

The print_r() result is randomized, but here’s one example:

Array
(
    [0] => 4
    [1] => 1
    [2] => 3
    [3] => 5
    [4] => 2
)

Keep in mind that the shuffle() function resets the array key pointers.

If you have an associative array, the function will replace the keys with numbers when you call it:

<?php

// shuffle an associative array
$arr = [
    "user" => "Nathan",
    "age" => 28,
    "likes" => ["PHP", "JavaScript"]
];

shuffle($arr);

print_r($arr);

The resulting array will be as shown below:

Array
(
    [0] => 28
    [1] => Array
        (
            [0] => PHP
            [1] => JavaScript
        )

    [2] => Nathan
)

To keep the keys of your associative array, you need to use the array_keys() together with the shuffle() function.

See the following example:

<?php

$arr = [
    "user" => "Nathan",
    "age" => 28,
    "likes" => ["PHP", "JavaScript"]
];

// 👇 get the array keys
$keys = array_keys($arr);

// 👇 shuffle the keys
shuffle($keys);

// 👇 use foreach to create a new array order
foreach($keys as $k) {
    $new_array[$k] = $arr[$k];
}

// 👇 assign new array to array
$arr = $new_array;

// 👇 print the result
print_r($arr);

Here’s the output of the code above:

Array
(
    [user] => Nathan
    [likes] => Array
        (
            [0] => PHP
            [1] => JavaScript
        )

    [age] => 28
)

Now you’ve learned how to shuffle arrays in PHP.

Shuffling an associative array is a little more complex than shuffling a regular array.

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