public function reduce(callable $callback, $initial = null)
    {
        return i\iterable_reduce($this->iterable, $callback, $initial);
    }
public function reduce(callable $callback, $initial = null)
    {
        return i\iterable_reduce($this->iterable, $callback, $initial);
    }
public function reduce ( callable $ callback , $ initial = null ) { return i \ iterable_reduce ( $ this -> iterable , $ callback , $ initial ) ; }
Reduce all elements to a single value using a callback.

@param callable  $callback
@param mixed     $initial
@return mixed
Reduce all elements to a single value using a callback .