PHP Functions for Randomly Shuffling Arrays

In PHP, there are several functions that can randomly shuffle an array, changing the order of its elements.

1. shuffle()

The shuffle() function directly shuffles the given array, modifying its internal element order.

<?php
$arr = [1, 2, 3, 4, 5];
shuffle($arr);
print_r($arr); // outputs the shuffled array
?>

2. array_rand()

The array_rand() function returns a specified number of random keys from the array; using these keys you can reorder the array.

<?php
$arr = [1, 2, 3, 4, 5];
$keys = array_rand($arr, 3); // randomly return 3 keys
$sortedArr = [];
foreach ($keys as $key) {
    $sortedArr[] = $arr[$key];
}
print_r($sortedArr); // outputs the reordered array
?>

Practical Example:

Suppose you have a list of student names that need to be randomly assigned to different classes. The following code demonstrates how to achieve this:

<?php
$students = ['John', 'Mary', 'Bob', 'Alice', 'Tom'];
shuffle($students);
// Divide students into 2 classes
$class1 = array_slice($students, 0, 3);
$class2 = array_slice($students, 3);
print_r($class1); // outputs students in the first class
print_r($class2); // outputs students in the second class
?>

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