array_diff_ukey
array_fill_keys
Array Functions
PHP Manual

# array_diff

(PHP 4 >= 4.0.1, PHP 5, PHP 7)

array_diff — Computes the difference of arrays

### Description

array array_diff ( array `$array1` , array `$array2` [, array `$...` ] )

Compares `array1` against one or more other arrays and returns the values in `array1` that are not present in any of the other arrays.

### Parameters

`array1`

  The array to compare from

`array2`

  An array to compare against

`...`

  More arrays to compare against

### Return Values

Returns an array containing all the entries from `array1` that are not present in any of the other arrays.

### Examples

Example #1 array_diff() example

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

Multiple occurrences in $array1 are all treated the same way. This will output :

    Array
    (
        [1] => blue
    )

### Notes

> Note:

> Two elements are considered equal if and only if (string) $elem1 === (string) $elem2. In words: when the string representation is the same.

> Note:

> This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using array_diff($array1[0], $array2[0]);.

### See Also

- array_diff_assoc() - Computes the difference of arrays with additional index check
- array_intersect() - Computes the intersection of arrays
- array_intersect_assoc() - Computes the intersection of arrays with additional index check

array_diff_ukey
array_fill_keys
Array Functions
PHP Manual