Пытаюсь добавить метод добавления в связанный список ⇐ Python

[Гость]

I'm trying to create a prepend method that takes the value and insert it between the head and the next value in the linked list, and here is where I am at the moment, it only prints none < because of the print statement and then it prints just 1:

Код: Выделить всё

class Node:         def __init__(self, value):             self.value = value             self.next = None class LinkedList:     def __init__(self):         self.head = None     def append(self, value):         if self.head is None:             self.head = Node(value)             return         # Move to the tail (the last node)         node = self.head         while node.next:             node = node.next         node.next = Node(value)         return     def prepend(self,value):         if self.head is None:             self.head = Node(value)             return         else:             holder = None             self.head.next = holder             #holder.next = holder             print(holder)         return linked_list = LinkedList() linked_list.append(1) linked_list.append(2) linked_list.append(4) linked_list.prepend(5) node = linked_list.head while node:     print(node.value)     node = node.next 

do you have any idea how to do that or fix my logic and please explean to me step by step how did you came up with the solution. P.S: I'm a beginner.


Источник: https://stackoverflow.com/questions/609 ... inked-list