php - abs of an array

Question

Which is the easy way of getting the abs of an array in php? It has to be a better way. This works, but in multidimensional array it has some limitations

function make_abs($numbers) {
 $abs_array = array();

 foreach($numbers as $key=>$value)
   $abs_array[$key] = abs($value);

 return $abs_array;
}

question from:https://stackoverflow.com/questions/65928064/absolute-value-implode

Answer 1

Your variant using references (this does not solve your recursion problem, just FYI):

function make_abs(&$numbers)
{
    foreach($numbers as &$value)
        $value = abs($value)
    ;
}

For the recursion problem, you need to step into each array:

function make_abs(&$numbers)
{
    foreach($numbers as &$value)
        is_array($value) ? make_abs($value) : $value = abs($value)
    ;
}

PHP itself has a somewhat handy function for that, array_walk_recursive^Docs. The problem with that function is, it expects the callback to have two parameters, value (by reference) and key. Many PHP functions do not fit those requirements. You can work around that by creating yourself a helper function to use any function that only takes one parameter and returns the modified value. You pass the function as with array_map^Docs:

function array_walk_recursive_map(array &$array, $callback)
{
    $byRef = function(&$item, $key) use ($callback)
    {
        $item = $callback($item);
    };
    array_walk_recursive($array, $byRef);
}

# Usage:
array_walk_recursive_map($numbers, 'abs');

Hope this is helpful.