PHP Manual: Shuffle an array

Description

true shuffle(array &$array)

This function shuffles (randomizes the order of the elements in) an array.

Caution

This function does not generate cryptographically secure values, and must not be used for cryptographic purposes, or purposes that require returned values to be unguessable.

If cryptographically secure randomness is required, the Random\Randomizer may be used with the Random\Engine\Secure engine. For simple use cases, the random_int and random_bytes functions provide a convenient and secure API that is backed by the operating system’s CSPRNG.

Parameters

array: The array.

Return Values

Always returns true.

Changelog

Version	Description
7.1.0	The internal randomization algorithm has been changed to use the » Mersenne Twister Random Number Generator instead of the libc rand function.

Examples

Example #1 shuffle example

<?php
$numbers = range(1, 20);
shuffle($numbers);
foreach ($numbers as $number) {
    echo "$number ";
}
?>

Notes

Note: This function assigns new keys to the elements in array. It will remove any existing keys that may have been assigned, rather than just reordering the keys.

Note:
Resets array's internal pointer to the first element.

shuffle