(PHP 5 >= 5.5.0)
SplDoublyLinkedList::add — Add/insert a new value at the specified index
Insert the value newval at the
specified index, shuffling the
previous value at that index (and all subsequent values)
up through the list.
indexThe index where the new value is to be inserted.
newval
The new value for the index.
Эта функция не возвращает значения после выполнения.
Throws OutOfRangeException when
index is out of bounds or when
index cannot be parsed as an integer.