How to get random value out of an array

Question

I have an array called $ran = array(1,2,3,4);

I need to get a random value out of this array and store it in a variable, how can I do this?

Answer 1

PHP provides a function just for that: array_rand()
http://php.net/manual/en/function.array-rand.php

$ran = array(1,2,3,4);
$randomElement = $ran[array_rand($ran, 1)];

Answer 2

You get a random number out of an array as follows:

$randomValue = array_rand($rand,1);

Answer 3

Does your selection have any security implications? If so, use random_int() and array_keys(). (random_bytes() is PHP 7 only, but there is a polyfill for PHP 5).

function random_index(array $source)
{
    $max = count($source) - 1;
    $r = random_int(0, $max);
    $k = array_keys($source);
    return $k[$r];
}

Usage:

$array = [
    'apple' =>   1234,
    'boy'   =>   2345,
    'cat'   =>   3456,
    'dog'   =>   4567,
    'echo'  =>   5678,
    'fortune' => 6789
];
$i = random_index($array);
var_dump([$i, $array[$i]]);

Demo: https://3v4l.org/1joB1

Answer 4

Derived from Laravel Collection::random():

function array_random($array, $amount = 1)
{
    $keys = array_rand($array, $amount);

    if ($amount == 1) {
        return $array[$keys];
    }

    $results = [];
    foreach ($keys as $key) {
        $results[] = $array[$key];
    }

    return $results;
}

Usage:

$items = ['foo', 'bar', 'baz', 'lorem'=>'ipsum'];

array_random($items); // 'bar'
array_random($items, 2); // ['foo', 'ipsum']

A few notes:

• $amount has to be less than or equal to count($array).
• array_rand() doesn't shuffle keys (since PHP 5.2.10, see 48224), so your picked items will always be in original order. Use shuffle() afterwards if needed.

Documentation: array_rand(), shuffle()

edit: The Laravel function has noticeably grown since then, see Laravel 5.4's Arr::random(). Here is something more elaborate, derived from the grown-up Laravel function:

function array_random($array, $number = null)
{
    $requested = ($number === null) ? 1 : $number;
    $count = count($array);

    if ($requested > $count) {
        throw new \RangeException(
            "You requested {$requested} items, but there are only {$count} items available."
        );
    }

    if ($number === null) {
        return $array[array_rand($array)];
    }

    if ((int) $number === 0) {
        return [];
    }

    $keys = (array) array_rand($array, $number);

    $results = [];
    foreach ($keys as $key) {
        $results[] = $array[$key];
    }

    return $results;
}

A few highlights:

• Throw exception if there are not enough items available
• array_random($array, 1) returns an array of one item (#19826)
• Support value "0" for the number of items (#20439)

Answer 5

You can use mt_rand()

$random = $ran[mt_rand(0, count($ran) - 1)];

This comes in handy as a function as well if you need the value

function random_value($array, $default=null)
{
    $k = mt_rand(0, count($array) - 1);
    return isset($array[$k])? $array[$k]: $default;
}

Answer 6

You can also do just:

$k = array_rand($array);
$v = $array[$k];

This is the way to do it when you have an associative array.