Master PHP’s array_chunk(): Split Large Arrays Efficiently

In PHP development, handling arrays is common; sometimes you need to split a large array into smaller chunks of a specified size. This article explains the array_chunk() function and provides code examples.

The syntax of array_chunk() is:

array array_chunk ( array $array , int $size [, bool $preserve_keys = false ] )

The function accepts three parameters: $array – the array to split, $size – the size of each chunk, and $preserve_keys – whether to preserve original keys.

Example: splitting an array into chunks of size 3.

<?php
$array = array('a','b','c','d','e','f','g','h','i','j');
$chunks = array_chunk($array, 3);
print_r($chunks);
?>

The output shows the original array divided into four sub‑arrays, each containing three elements except the last one.

To preserve keys, set the third argument $preserve_keys to true.

<?php
$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5, 'f' => 6);
$chunks = array_chunk($array, 2, true);
print_r($chunks);
?>

The result is three sub‑arrays that retain the original associative keys.

Summary

The array_chunk() function is a practical PHP array utility that can split a large array into multiple smaller arrays, optionally preserving keys, helping developers handle large data sets more conveniently.