PHP’s array_walk_recursive
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.
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.
/**
* 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 to alter $array to get a short slice of each value
* array_walk_recursive_by_reference(
* $array, "substr", array("1","3")
* );
*/
function array_walk_recursive_by_reference(
&$array, $function, $parameters = array()) {
$reference_function = function(&$value, $key, $data) {
$parameters = array_merge(array($value), $data[1]);
$value = call_user_func_array($data[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.
