Python链接列表的总和

Question

这些是我的代码

class Node():
'''A node in a linked list'''
    def __init__(self, data, next_node=None):
        self.data = data
        self.next_node = next_node

def sum(LL):
    head = LL
    # If Linked list is empty, return 0
    if (head.data is None or head.data == []):
        result = 0
    # If Linked List contain only 1 node then return it
    elif (head.next_node is None):
        result = head.data
    else:
        curr = head
        result = curr.data
        # If next is not None then add up to result
        while (curr.next_node is not None):
            curr = curr.next_node
            result += curr.data
    return result

问题在代码的末尾

while (curr.next_node is not None):
    curr = curr.next_node
    result += curr.data

如果我尝试这个

LL = Node(1, Node(2, 3))
sum(LL)

我不明白为什么它说

hindins.attributeerror：'int'对象没有属性'data'

while循环工作直到达到最后一个节点

结果应为6

Answer 1

，因为 3是您的下一个节点。您可能想要：

LL = Node(1, Node(2, Node(3)))

Answer 2

您指向一个不存在的节点。第二个嵌套节点指向下一个节点3，但是该节点不存在母猪，它去寻找其数据，找不到任何地方。

Answer 3

如何呢？通过链接列表创建迭代器以迭代。然后，您有一个标准迭代器，只需用内置的总和函数总结：

def traverse(LL):
    head = LL
    while (head):
        yield head.data
        head = head.next_node

sum(traverse(LL))