如何实例化 class 并打印值

Question

希望有人可以在这里给我提示 - 所以我有一个节点 class 应该接收 1 个强制值和一个可选值。思路是return一个链表

class Node(object):
    def __init__(self, value, next_node = None):
        self.value = value
        self.next_node = next_node

    def get_next(self):
        return self.next_node

现在我正在使用这个 class 创建一个链接列表，例如：

Z = Node('Z')
Y = Node('Y', Z)
X = Node('X', Y)
W = Node('W', X)

现在我想写一个接收列表头部并打印它的函数:

def print_reverse(head):
    current = head
    my_list = []
    while current:
        current = current.next_node
        u = Node(current)
        my_list.append(u.value)
    print my_list

print_reverse(W)

我面临的问题是我取回了内存地址而不是实际值。

[<__main__.Node object at 0x1033eb390>, <__main__.Node object at 0x1033eb350>, <__main__.Node object at 0x1033eb310>, None]

基本上我不知道如何实例化Node的值。我想取回这个

[ W, X, Y , Z, None]

Answer 1

您需要实现 repr，它应该 return 对象的可打印表示。例如

class Node(object):
    def __init__(self, value, next_node = None):
        self.value = value
        self.next_node = next_node

    def get_next(self):
        return self.next_node

    def __repr__(self):
        return self.value

https://docs.python.org/2/reference/datamodel.html#object.repr

Answer 2

class Node(object):
    def __init__(self, value, next_node = None):
        self.value = value
        self.next_node = next_node

    def get_next(self):
        return self.next_node

def print_reverse(head):
    current = head
    my_list = []
    my_list.append(current.value)
    while current.next_node != None:
        current = current.next_node
        my_list.append(current.value)
    print my_list

Z = Node('Z')
Y = Node('Y', Z)
X = Node('X', Y)
W = Node('W', X)
print_reverse(W)

这会为我运行并打印 ['W'、'X'、'Y'、'Z']。

如何实例化 class 并打印值

how to instantiate a class and print the value

python

class

instantiation