Use array_merge_recursive for unknown number of arrays

I have a PHP script where I get a random number of arrays nested inside an array and need to merge them using array_merge_recursive. Given the number of nested arrays is always variable, is there a way to use array_merge_recursive in this scenario? I am looking to do something to the effect of the following in a dynamic manner.

array_merge_recursive($arr[0], $arr[1], $arr[2], etc);

Answer

You can use call_user_func_array() and each element (array) of $arr will be passed as individual arguments:

$result = call_user_func_array('array_merge_recursive', $arr);

You can also use argument unpacking ... which will unpack each element of $arr into individual arguments:

$result = array_merge_recursive(...$arr);