PHP array_intersect_key() Function

Example

Compare the keys of two arrays, and return the matches:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","c"=>"blue","d"=>"pink");

$result=array_intersect_key($a1,$a2);
print_r($result);
?>

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Definition and Usage

The array_intersect_key() function compares the keys of two (or more) arrays, and returns the matches.

This function compares the keys of two or more arrays, and return an array that contains the entries from array1 that are present in array2, array3, etc.

Syntax

array_intersect_key( array1, array2, array3, ...)

Parameter Values

Parameter	Description
array1	Required. The first array is the array that the others will be compared with
array2	Required. An array to be compared with the first array
array3,...	Optional. An array to be compared with the first array

Technical Details

Return Value:	Returns an array containing the entries from array1 that are present in all of the other arrays
PHP Version:	5.1.0+

More Examples

Example

Compare the keys of two indexed arrays, and return the matches:

<?php
$a1=array("red","green","blue","yellow");
$a2=array("red","green","blue");

$result=array_intersect_key($a1,$a2);
print_r($result);
?>

Try it Yourself »

Example

Compare the keys of three arrays, and return the matches:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("c"=>"yellow","d"=>"black","e"=>"brown");
$a3=array("f"=>"green","c"=>"purple","g"=>"red");

$result=array_intersect_key($a1,$a2,$a3);
print_r($result);
?>

Try it Yourself »

❮ PHP Array Reference