PHP array_multisort Function

last modified March 13, 2025

The PHP array_multisort function sorts multiple arrays or a multidimensional array by one or more dimensions. It's powerful for complex sorting scenarios.

Basic Definition

array_multisort can sort several arrays at once or a multi- dimensional array by one or more columns. It maintains index association.

Syntax: array_multisort(array &$array1 [, mixed $array1_sort_order = SORT_ASC [, mixed $array1_sort_flags = SORT_REGULAR [, mixed $... ]]]): bool.

Sorting Two Parallel Arrays

This example demonstrates sorting two arrays where one array acts as sort key.

parallel_arrays.php

<?php

$names = ["Tom", "Alice", "Bob"];
$ages = [25, 22, 30];

array_multisort($ages, SORT_ASC, $names);

print_r($names); 
print_r($ages);

Here we sort both arrays by age in ascending order. The $names array is rearranged to match the sorted $ages array order.

Sorting a Multidimensional Array

Sort a multidimensional array by one of its columns while maintaining structure.

multidimensional_array.php

<?php

$users = [
    ["name" => "Tom", "age" => 25],
    ["name" => "Alice", "age" => 22],
    ["name" => "Bob", "age" => 30]
];

$ages = array_column($users, 'age');
array_multisort($ages, SORT_ASC, $users);

print_r($users);

This sorts the $users array by age in ascending order. We first extract the age column, then use it as the sort key for the main array.

Sorting by Multiple Columns

Sort a multidimensional array by multiple columns with different sort orders.

multiple_columns.php

<?php

$products = [
    ["name" => "Laptop", "price" => 999, "stock" => 5],
    ["name" => "Phone", "price" => 699, "stock" => 10],
    ["name" => "Tablet", "price" => 399, "stock" => 8],
    ["name" => "Monitor", "price" => 199, "stock" => 3]
];

$prices = array_column($products, 'price');
$stocks = array_column($products, 'stock');

array_multisort(
    $prices, SORT_ASC,
    $stocks, SORT_DESC,
    $products
);

print_r($products);

This sorts products by price ascending, then by stock descending. The primary sort is on price, with stock used to break ties between equal prices.

Case-Insensitive String Sorting

Sort string arrays case-insensitively using the SORT_FLAG_CASE flag.

case_insensitive.php

<?php

$fruits = ["apple", "Orange", "banana", "PEAR"];
array_multisort($fruits, SORT_ASC, SORT_FLAG_CASE | SORT_STRING);

print_r($fruits);

The SORT_FLAG_CASE flag makes the sort case-insensitive. Without it, uppercase letters would sort before lowercase ones.

Natural Order Sorting

Sort strings containing numbers in natural human order using SORT_NATURAL.

natural_sort.php

<?php

$versions = ["version1", "version10", "version2", "version20"];
array_multisort($versions, SORT_ASC, SORT_NATURAL);

print_r($versions);

Natural sorting treats numeric parts of strings as numbers rather than text. This produces more intuitive results for version numbers or filenames.

Best Practices

Reference Parameters: Remember arrays are passed by reference.
Column Extraction: Use array_column() for multidimensional arrays.
Flag Combinations: Combine flags like SORT_NATURAL | SORT_FLAG_CASE.
Error Handling: Check return value as it returns bool.
Memory: Be mindful with large arrays as it sorts in-place.

Source

PHP array_multisort Documentation

This tutorial covered the PHP array_multisort function with practical examples showing its usage for various sorting scenarios.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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