PHP: array_intersect_key

Description

array array_intersect_key ( array array1, array array2 [, array ...] )

array_intersect_key() returns an array containing all the values of array1 which have matching keys that are present in all the arguments.

Beispiel 1. array_intersect_key() example

<?php $array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4); $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8); var_dump(array_intersect_key($array1, $array2)); ?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
array(2) { ["blue"]=> int(1) ["green"]=> int(3) })

In our example you see that only the keys 'blue' and 'green' are present in both arrays and thus returned. Also notice that the values for the keys 'blue' and 'green' differ between the two arrays. A match still occurs because only the keys are checked. The values returned are those of array1.

The two keys from the key => value pairs are considered equal only if (string) $key1 === (string) $key2 . In other words a strict type check is executed so the string representation must be the same.

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array_intersect_key

Silvio Ginter
23-Sep-2005 02:17


Based on the code posted by gaylord dot aulke at 100days.de

i wrote this one. This should implement this function in all versions equal or greater than PHP 4.0



function array_intersect_key($arr1, $arr2) {

    $res = array();

    foreach($arr1 as $key=>$value) {

        $push = true;

        for ($i = 1; $i < func_num_args(); $i++) {

            $actArray = func_get_arg($i);

            if (gettype($actArray) != 'array') return false;

            if (!array_key_exists($key, $actArray)) $push = false;

        }

        if ($push) $res[$key] = $arr1[$key];

    }

    return $res;

}

gaylord dot aulke at 100days.de
04-Jul-2005 01:04


I tried to use this function with PHP 5.0.4 under windows but the function does not seem to be implemented. 

(Fatal error: Call to undefined function array_intersect_key())



This works as a workaround for 2 arrays at least:



function array_intersect_key($arr1, $arr2) {

  $res = array();

  foreach($arr1 as $key=>$value) {

    if(array_key_exists($key, $arr2)) $res[$key] = $arr1[$key];

  }

  return $res;

}

aidan at php dot net
29-May-2005 05:51


This functionality is now implemented in the PEAR package PHP_Compat.



More information about using this function without upgrading your version of PHP can be found on the below link:



http://pear.php.net/package/PHP_Compat

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