PHP: array_walk_recursive

Description

bool array_walk_recursive ( array &input, callback funcname [, mixed userdata] )

Applies the user-defined function funcname to each element of the input array. This function will recur into deeper arrays. Typically, funcname takes on two parameters. The input parameter's value being the first, and the key/index second. If the optional userdata parameter is supplied, it will be passed as the third parameter to the callback funcname.

Returns TRUE on success or FALSE on failure.

Note: If funcname needs to be working with the actual values of the array, specify the first parameter of funcname as a reference. Then, any changes made to those elements will be made in the original array itself.

Example 1. array_walk_recursive() example

<?php $sweet = array('a' => 'apple', 'b' => 'banana'); $fruits = array('sweet' => $sweet, 'sour' => 'lemon'); function test_print($item, $key) { echo "$key holds $item\n"; } array_walk_recursive($fruits, 'test_print'); ?>
The above example will output:

a holds apple b holds banana sour holds lemon
You may notice that the key 'sweet' is never displayed. Any key that holds an array will not be passed to the function.

See also array_walk(), and information about the callback type.

User Contributed Notes
array_walk_recursive

aidan at php dot net
22-Feb-2005 01:10


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

hannes (at) tismer.com
14-Dec-2004 01:08


I wondered about an array_mergedown function working with PHP4, using an array_walk_recursive-like function which just merges any number of arrays of any dimension to a one dimension array containing every key=>value part of all arrays:





<?php


function array_mergedown() {


    global $outarray;


    $outarray = array();


    function array_walk_recphp4(&$val,$key) {


        global $outarray;


        if (is_array($val)) array_walk($val,'array_walk_recphp4');


        else {


            $outarray[$key] = $val;


        }


    }


    $params = func_get_args();


    foreach ($params as $subarr) {


        array_walk_recphp4($subarr, '');


    }


    return $outarray;


}


?>





For testing:





<?php


$arr1[]["foo1"] = "bar1";


$arr2["foo2"] = "bar2";


$arr2[12] = "bar3";


$arr2[10]["foo4"] = "bar4";


$arr2[]["foo4"][0]["foo5"] = "bar5";


$arr3 = "nono";





print_r(array_mergedown($arr1, $arr2, $arr3));


?>





returns:


Array ( [foo1] => bar1 [foo2] => bar2 [12] => bar3 [foo4] => bar4 [foo5] => bar5 )





I hope this helped someone :)

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