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14 years ago
The description says "If funcname needs to be working with the actual values of the array, specify the first parameter of funcname as a reference." This isn't necessarily helpful as the function you're calling might be built in (e.g. trim or strip_tags). One option would be to create a version of these like so.



<?php

    function trim_by_reference(&$string) {

        $string = trim($string);

    }

?>



The downside to this approach is that you need to create a wrapper function for each function you might want to call. Instead, we can use PHP 5.3's inline function syntax to create a new version of array_walk_recursive.



<?php

    /**

     * This function acts exactly like array_walk_recursive, except that it pretends that the function

     * its calling replaces the value with its result.

     * 

     * @param $array The first value of the array will be passed into $function as the primary argument

     * @param $function The function to be called on each element in the array, recursively

     * @param $parameters An optional array of the additional parameters to be appeneded to the function

     * 

     * Example usage to alter $array to get the second, third and fourth character from each value

     *     array_walk_recursive_referential($array, "substr", array("1","3"));

     */

    function array_walk_recursive_referential(&$array, $function, $parameters = array()) {

        $reference_function = function(&$value, $key, $userdata) {

            $parameters = array_merge(array($value), $userdata[1]);

            $value = call_user_func_array($userdata[0], $parameters);

        };

        array_walk_recursive($array, $reference_function, array($function, $parameters));

    }

?>



The advantage here is that we only explicitly define one wrapper function instead of potentially dozens.
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