PHP: array_intersect_assoc

Description

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

array_intersect_assoc() returns an array containing all the values of array1 that are present in all the arguments. Note that the keys are used in the comparison unlike in array_intersect().

Example 1. array_intersect_assoc() example

<?php $array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red"); $array2 = array("a" => "green", "yellow", "red"); $result_array = array_intersect_assoc($array1, $array2); ?>
$result_array will look like:
Array ( [a] => green )

In our example you see that only the pair "a" => "green" is present in both arrays and thus is returned. The value "red" is not returned because in $array1 its key is 0 while the key of "red" in $array2 is 1.

The two values from the key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In other words a strict type check is executed so the string representation must be the same.

User Contributed Notes
array_intersect_assoc

vandor at progressive dot hu
14-Dec-2004 01:26


# ket tomb kulcs alapu metszetet szamitja ki, az erteken is ellenorzest vegez

#

# calculating (key base) intersection of arrays (value are checked)

# use: $result_array = array_intersect_assoc($a1, $a2, $a3,..);

#

##

# original code by [jochem at iamjochem dawt com] : array_diff_keys()



<?php

function array_intersect_assoc() {



    $args = func_get_args();

    $res = $args[0];



    for ($i=1;$i<count($args);$i++) {

        if (!is_array($args[$i])) {continue;}



        foreach ($res as $key => $data) {

            if ( (!array_key_exists($key, $args[$i])) || ( (isset($args[$i][$key])) && ($args[$i][$key] !== $res[$key]) ) ) {

                unset($res[$key]);

            }

        }

    }



    return $res;

}



?>



<?php

$array1 = array("a"=>"green", "b"=>"brown", "c"=>"blue", "red");

$array2 = array("a"=>"green", "b"=>"yellow", "c"=>"yellow", "red");

$a = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow');

$b = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow', 'e'=>'yellow');



$result_array = array_intersect_assoc($a, $b, $array1, $array2);

?>



$args array will look like:



(

    0 => 

        (

            a => green

            b => brown

            c => yellow

        )



    1 => 

        (

            a => green

            b => brown

            c => yellow

            e => yellow

        )



    2 => 

        (

            a => green

            b => brown

            c => blue

            0 => red

        )



    3 => 

        (

            a => green

            b => yellow

            c => yellow

            0 => red

        )



)



$result_array will look like:



(

    a => green

)

nleippe at integr8ted dot com
11-Feb-2004 06:46


A combination of the two functions [array_intersect() and array_intersect_assoc()] in order to obtain the intersection of two multidimensional arrays.





<?php


function array_intersect_assoc_recursive(&$arr1, &$arr2) {


    if (!is_array($arr1) || !is_array($arr2)) {


        return $arr1 == $arr2; // or === for strict type


    }


    $commonkeys = array_intersect(array_keys($arr1), array_keys($arr2));


    $ret = array();


    foreach ($commonkeys as $key) {


        $ret[$key] =& array_intersect_assoc_recursive($arr1[$key], $arr2[$key]);


    }


    return $ret;


}


?>