PHP array_diff function

array_diff

(PHP 4 >= 4.0.1, PHP 5)

array_diff -- Computes the difference of arraysDescriptionarray array_diff ( array array1, array array2 [, array ...] )

array_diff() returns an array
containing all the values of array1
that are not present in any of the other arguments.
Note that keys are preserved.

Example 1. array_diff() example

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

Array
(
[1] => blue
)

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

Note:
Please note that 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]);.

Warning

This was broken in PHP 4.0.4!

See also array_diff_assoc(),
array_intersect(), and
array_intersect_assoc().