PHP Array_diff_key ()

Definition and usage

The Array_diff_key () function returns an array that contains all the keys in the array being compared, but not in any other parameter array.

Grammar

Array_diff_key (Array1,array2,array3 ...)

Parameters	Describe
Array1	Necessary. The first array to compare with the other array.
Array2	Necessary. The array to compare with the first array.
Array3	Optional. The array to compare with the first array. Can have more than one.

Hints and Notes

Tip: You can use one or any number of arrays to compare to the first array.

Note: Only key names are used for comparisons.

Example

<?php$a1=array (0=> "Cat",1=> "Dog",2=> "Horse"), $a 2=array (2=> "Bird",3=> "Rat",4=> "Fish"); $a 3 = Array (5=> "Horse",6=> "Dog",7=> "Bird");p Rint_r (Array_diff_key ($a 1, $a 2, $a 3)); >

Output:

Array ([0] = Cat [1] = Dog)

PHP Array_diff_key ()