PHP array_intersect_key() Function

The PHP array_intersect_key() function compares keys of an array against one or more other arrays and returns all elements of the first array that are present in all the arguments.

The array_intersect() function is like this function except the comparison is done on the values instead of the keys.

Syntax

array_intersect_key(array, arrays)

Parameters

`array`	`Required.` Specify an array to compare from.
`arrays`	`Required.` Specify one or more arrays to compare against.

Return Value

Returns an array containing all the entries from array which have keys that are present in all the arguments.

Exceptions

NA.

Example:

The example below shows the usage of array_intersect_key() function.

<?php
$Arr1 = array("a"=>"Red",
              "b"=>"Red",
              "c"=>"Blue",
              "d"=>"Blue",
              "e"=>"Green");
$Arr2 = array("a"=>"Red", 
              "b"=>"Blue", 
              "c"=>"Green");

//comparing Arr1 against Arr2
$Arr1_intersect_Arr2 = array_intersect_key($Arr1, $Arr2);
print_r($Arr1_intersect_Arr2);
?>

The output of the above code will be:

Array
(
    [a] => Red
    [b] => Red
    [c] => Blue
)

❮ PHP Array Reference