PHP array_intersect_key() Function
Topic: PHP Array ReferencePrev|Next
Description
The array_intersect_key() function compares the keys of two or more arrays and returns the matches. The keys values are not considered in the comparison, only the keys are checked.
The following table summarizes the technical details of this function.
| Return Value: | Returns an array containing all the elements from array1 whose keys are present in all of the other arrays. |
|---|---|
| Version: | PHP 5.1.0+ |
Syntax
The basic syntax of the array_intersect_key() function is given with:
The following example shows the array_intersect_key() function in action.
Example
Run this code »<?php
// Sample arrays
$array1 = array("a"=>"apple", "b"=>"ball", "c"=>"cat", "dog");
$array2 = array("a"=>"apricot", "b"=>"banana");
// Computing the intersection
$result = array_intersect_key($array1, $array2);
print_r($result);
?>Parameters
The array_intersect_key() function accepts the following parameters.
| Parameter | Description |
|---|---|
| array1 | Required. Specifies the array to compare from. |
| array2 | Required. Specifies an array to compare keys against. |
| ... | Optional. Specifies more arrays to compare keys against. |
More Examples
Here're some more examples showing how array_intersect_key() function actually works:
In the following example this function compares an array against two other arrays.
Example
Run this code »<?php
// Sample arrays
$array1 = array("a"=>"apple", "b"=>"ball", "c"=>"cat", "dog");
$array2 = array("a"=>"apricot", "b"=>"banana");
$array3 = array("a"=>"alligator", "d"=>"dog");
// Computing the intersection
$result = array_intersect_key($array1, $array2, $array3);
print_r($result);
?>The two keys from the key=>value pairs are considered equal if their string representation are same, i.e., (string) $key1 === (string) $key2. Let's try out the following example:
Example
Run this code »<?php
// Sample arrays
$array1 = array(1, 2, 5, 7, 10);
$array2 = array(0, "1"=>3, "x"=>8, "4"=>13);
// Computing the intersection
$result = array_intersect_key($array1, $array2);
print_r($result);
?>
