PHP : Computes the difference between multidimensional arrays

array_diff_multidimensional.php

<?php
/**
 * Computes the difference between two arrays
 *
 * @param array $array1
 * @param array $array2
 * @return array
 */
function array_diff_two( $array1, $array2 ) {
	$diff = array();

	// Check the similarities
	foreach( $array1 as $k1 => $v1 ) {
		if ( isset( $array2[$k1] ) ) {
			$v2 = $array2[$k1];
			if ( is_array( $v1 ) && is_array( $v2 ) ){
				// 2 arrays: just go further...
				// .. and explain it's an update!
				$changes = array_diff_two( $v1, $v2 );
				if ( count( $changes ) > 0 ){
					// If we have no change, simply ignore
					$diff[$k1] = $changes;
				}
				unset( $array2[$k1] ); // don't forget
			}
			else if ( $v2 === $v1 ){
				// unset the value on the second array
				// for the "surplus"
				unset( $array2[$k1] );
			}
			else {
				// Don't mind if arrays or not.
				$diff[$k1] = $v2;
				unset( $array2[$k1] );
			}
		}
		else {
			// remove information
			$diff[$k1] = $v1; 
		}
	}

	reset( $array2 );
	foreach ( $array2 as $key => $value ){
		$diff[$key] = $value;
	}
	return $diff;
}

/**
 * Computes the difference of arrays
 *
 * @param array $array1 
 * @param array $array2
 * @param array $...
 * @return array
 */
function array_difference() {
	$arguments = func_get_args();
	$diff = array();

	foreach ( $arguments as $key => $array ) {
		$diff = array_diff_two( $diff, $array );
	}

	return $diff;
}

$array1 = array(
	"a" => "green",
	"b" => array(
		"id" => 1,
		"ids" => 1
	),
	"red"
);
$array2 = array(
	"a" => "green",
	"b" => array(
		"id" => 2
	),
	"yellow",
	"red"
);
$array3 = array(
	"a" => "blue",
	"b" => array(),
	"navy",
	"red"
);

$result = array_difference( $array1, $array2, $array3 );

print_r($result);
?>