README

(PHP 5 >= 5.4)
array_group_by — Groups an array by a given key.

Description

array|null array_group_by( array $array, mixed $key1 [, mixed $... ] )

Groups an array into arrays by a given $key, or set of keys, shared between all array members.

Based on Jake Zatecky's array_group_by() function.

This fork offers:

• $key parameter can be a closure

Parameters

• $array — The array to have grouping performed on.

• $key — The key to group or split by. Can be a string, an integer, a float, or a callback. If the key is NULL, the iterated element is skipped. If the key is a callback, it must return a valid key from the array.

  string|int callback ( mixed $item )

• ... — Additional keys for grouping the next set of sub-arrays.

Return Values

Returns a multidimensional array, with each dimension containing elements grouped by the passed key(s).

Errors/Exceptions

If $key is not one of the accepted types E_USER_ERROR will be thrown and NULL returned.

Examples

Example #1 array_group_by() example

$records = [
	[
		"state"  => "IN",
		"city"   => "Indianapolis",
		"object" => "School bus"
	],
	[
		"state"  => "IN",
		"city"   => "Indianapolis",
		"object" => "Manhole"
	],
	[
		"state"  => "IN",
		"city"   => "Plainfield",
		"object" => "Basketball"
	],
	[
		"state"  => "CA",
		"city"   => "San Diego",
		"object" => "Light bulb"
	],
	[
		"state"  => "CA",
		"city"   => "Mountain View",
		"object" => "Space pen"
	]
];

$grouped = array_group_by( $records, "state", "city" );

The above example will output:

Array
(
	[IN] => Array
		(
			[Indianapolis] => Array
				(
					[0] => Array
						(
							[state] => IN
							[city] => Indianapolis
							[object] => School bus
						)

					[1] => Array
						(
							[state] => IN
							[city] => Indianapolis
							[object] => Manhole
						)

				)

			[Plainfield] => Array
				(
					[0] => Array
						(
							[state] => IN
							[city] => Plainfield
							[object] => Basketball
						)

				)

		)

	[CA] => Array
		(
			[San Diego] => Array
				(
					[0] => Array
						(
							[state] => CA
							[city] => San Diego
							[object] => Light bulb
						)

				)

			[Mountain View] => Array
				(
					[0] => Array
						(
							[state] => CA
							[city] => Mountain View
							[object] => Space pen
						)

				)

		)
)

Installation

With Composer

$ composer require mcaskill/php-array-group-by

Without Composer

Why are you not using composer? Download Function.Array-Group-By.php from the gist and save the file into your project path somewhere.