Array Functions
PHP Manual

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 other 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
  • array_intersect
  • array_intersect_assoc