【问题标题】：What is wrong with this linked list implementation? [closed]这个链表实现有什么问题？ [关闭]
【发布时间】：2020-07-18 13:27:04
【问题描述】：

运行脚本会产生错误：

Traceback (most recent call last):
  File "D:/PycharmProjects/GeeksforGeeks/Linked List/Insertion of Nodes in LinkedList.py", line 49, in <module>

llist.printList()
  File "D:/PycharmProjects/GeeksforGeeks/Linked List/Insertion of Nodes in LinkedList.py", line 39, in printList

违规行是：

print(temp.data,end=' ')

AttributeError: 'int' 对象没有属性 'data'

我的代码是：-

class Node:
    def __init__(self,data):
        self.data = data
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None

    def push(self,new_data):
        new_node = Node(new_data)
        new_node.next = self.head
        self.head = new_node

    def insertAfter(self,prev_node,new_data):
        if prev_node is None:
            return

        new_node = Node(new_data)
        new_node.next = prev_node.next
        prev_node.next = new_node

    def append(self,new_data):
        new_node = Node(new_data)

        if self.head is None:
            self.head = new_node
            return

        last = self.head
        while (last.next):
            last = last.next

        last.next = new_data

    def printList(self):
        temp = self.head
        while (temp):
            print(temp.data,end=' ')
            temp = temp.next

if __name__ == '__main__':
    llist = LinkedList()
    llist.append(6)
    llist.push(7)
    llist.push(1)
    llist.append(4)
    llist.insertAfter(llist.head.next,8)
    llist.printList()

【问题讨论】：

“追加”中的最后一行：“last.next = new_data”
您正在使最后一个节点中的next 链接指向数据，而不是指向包含数据的节点

标签： python singly-linked-list attributeerror

【解决方案1】：

在你的方法append，last.next应该是new_node

class Node:
    def __init__(self,data):
        self.data = data
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None

    def push(self,new_data):
        new_node = Node(new_data)
        new_node.next = self.head
        self.head = new_node

    def insertAfter(self,prev_node,new_data):
        if prev_node is None:
            return

        new_node = Node(new_data)
        new_node.next = prev_node.next
        prev_node.next = new_node

    def append(self,new_data):
        new_node = Node(new_data)

        if self.head is None:
            self.head = new_node
            return

        last = self.head
        while (last.next):
            last = last.next

        last.next = new_node

    def printList(self):
        temp = self.head
        while (temp):
            print(temp.data,end=' ')
            temp = temp.next

if __name__ == '__main__':
    llist = LinkedList()
    llist.append(6)
    llist.push(7)
    llist.push(1)
    llist.append(4)
    llist.insertAfter(llist.head.next,8)
    llist.printList()

输出：

1 7 8 6 4

【讨论】：

【解决方案2】：

append 函数中有一个错误：

    def append(self,new_data):
        new_node = Node(new_data)

        if self.head is None:
            self.head = new_node
            return

        last = self.head
        while last.next:
            last = last.next

        last.next = new_node # should not be new_data

【讨论】：