array_column() for PHP

This simple library provides functionality for array_column() to versions of PHP earlier than 5.5. It mimics the functionality of the built-in function in every way.

Usage

array array_column(array $input, mixed $columnKey[, mixed $indexKey])

Given a multi-dimensional array of data, array_column() returns the values from a single column of the input array, identified by the $columnKey. Optionally, you may provide an $indexKey to index the values in the returned array by the values from the $indexKey column in the input array.

For example, using the following array of data, we tell array_column() to return an array of just the last names, indexed by their record IDs.

<?php
$records = array(
    array(
        'id' => 2135,
        'first_name' => 'John',
        'last_name' => 'Doe'
    ),
    array(
        'id' => 3245,
        'first_name' => 'Sally',
        'last_name' => 'Smith'
    ),
    array(
        'id' => 5342,
        'first_name' => 'Jane',
        'last_name' => 'Jones'
    ),
    array(
        'id' => 5623,
        'first_name' => 'Peter',
        'last_name' => 'Doe'
    )
);

$lastNames = array_column($records, 'last_name', 'id');

If we call print_r() on $lastNames, you'll see a resulting array that looks a bit like this:

Array
(
    [2135] => Doe
    [3245] => Smith
    [5342] => Jones
    [5623] => Doe
)

Installation

The easiest way to install this library is to use Composer:

php composer.phar require ramsey/array_column

Then, when you run composer install, everything will fall magically into place, and the array_column() function will be available to your project, as long as you are including Composer's autoloader.

However, you do not need Composer to use this library.

This library has no dependencies and should work on older versions of PHP. Download the code and include src/array_column.php in your project, and all should work fine.

When you are ready to run your project on PHP 5.5, everything should continue to run well without conflicts, even if this library remains included in your project.