(PHP 4 >= 4.3.0, PHP 5)
array_diff_assoc — Computes the difference of arrays with additional index check
Compares array1 against array2 and returns the difference. Unlike array_diff() the array keys are used in the comparision.
The array to compare from
An array to compare against
More arrays to compare against
Returns an array containing all the values from array1 that are not present in any of the other arrays.
Example #1 array_diff_assoc() example
In this example you see the "a" => "green" pair is present in both arrays and thus it is not in the ouput from the function. Unlike this, the pair 0 => "red" is in the ouput because in the second argument "red" has key which is 1.
<?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 )
Note: This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example, array_diff_assoc($array1[0], $array2[0]);.