PHP Manual: Computes the difference of arrays with additional index check

Description

array array_diff_assoc(array $array, array ...$arrays)

Compares array against arrays and returns the difference. Unlike array_diff the array keys are also used in the comparison.

Parameters

array: The array to compare from
arrays: Arrays to compare against

Return Values

Returns an array containing all the values from array that are not present in any of the other arrays.

Changelog

Version	Description
8.0.0	This function can now be called with only one parameter. Formerly, at least two parameters have been required.

Examples

Example #1 array_diff_assoc example

In this example the "a" => "green" pair is present in both arrays and thus it is not in the output from the function. Unlike this, the pair 0 => "red" is in the output because the key of "red" is automatically assigned to 0 in the first array, whereas it is assigned to 1 in the second array as the key 0 is already taken by yellow.

<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "yellow", "red");
$result = array_diff_assoc($array1, $array2);
print_r($result);
?>

The above example will output:

Array
(
    [b] => brown
    [c] => blue
    [0] => red
)

Example #2 array_diff_assoc example

Two values from key => value pairs are considered equal only if (string) $elem1 === (string) $elem2. In other words a strict check takes place so the string representations must be the same.

<?php
$array1 = array(0, 1, 2);
$array2 = array("00", "01", "2");
$result = array_diff_assoc($array1, $array2);
print_r($result);
?>

The above example will output:

Array
(
    [0] => 0
    [1] => 1
)

Notes

Note: This function only checks one dimension of an n-dimensional array. It is possible to check deeper dimensions by using, for example, array_diff_assoc($array1[0], $array2[0]);.

Note: Ensure arguments are passed in the correct order when comparing similar arrays with more keys. The new array should be the first in the list.

array_diff_assoc