將節點 class 放入鏈表 class python

Question

這是我第一次學習python，只是想創建一個簡單的鏈表

這是代碼

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

class linked_list:
    
    def __init__(self):
        self.head = node()
        
    def append(self, data):
        new_node = node(data)
        cur = self.head
        while cur.next != None:
            cur = cur.next
        cur.next = new_node
    
    def length(self):
        cur = self.head
        total = 0
        while cur.next != None:
            total += 1 
            cur = cur.next
        return total
    
    @property
    def display(self):
        elems = []
        cur_node = self.head
        while cur_node.next != None:
            cur_node = cur_node.next
            elems.append(cur_node.data)
        print(elems)
    
    def get(self, index):
        if index >=  self.length():
            print('index out of range') 
            return None
        cur_idx = 0
        cur_node= self.head
        while True:
            cur_node = cur_node.next
            if cur_idx == index: return cur_node.data
            cur_idx+= 1
    
    def erase(self, index):
        if index >=  self.length():
            print('index out of range') 
            return None
        
        cur_idx = 0
        cur_node = self.head
        while True:
            last_node = cur_node
            cur_node = cur_node.next
            if cur_idx == index:
                last_node.next = cur_node.next
                return 
            cur_idx+= 1

l1 = linked_list()
l1.append(8)
l1.append(7)
l1.append(6)
l1.append(5)


print(l1.get(0))
print(l1.get(1))
print(l1.get(2))
print(l1.get(3))

一切都很順利，除非我嘗試將節點 class 放入鏈表 class 作為內部 class 如下所示：

class linked_list:
    class node:
        def __init__(self, data = None):
            self.data = data
            self.next = None
    
    
    def __init__(self):
        self.head = node()
        
    def append(self, data):
        new_node = node(data)
        cur = self.head
        while cur.next != None:
            cur = cur.next
        cur.next = new_node

......
(the rest are the same as the code above)

我收到了這個錯誤：

Traceback (most recent call last):
  File "c:\blahblah\Basic_exercise.py", line 65, in <module>
    l1 = linked_list()
  File "c:\blahblah\Basic_exercise.py", line 11, in __init__
    self.head = node()
NameError: name 'node' is not defined

1.我在這里錯過了什么邏輯？

2.有什么方法可以將節點 class 視為內部 class 而不會出錯？

Answer 1

您看到的錯誤是由於您引用內部 class 的方式 - 這是一個命名空間問題。 要從其他node類中消除內部node class 的歧義，您需要首先使用外部 class 來引用它： linked_list.node 。 例子：

class linked_list:
    class node:
        def __init__(self, data = None):
            self.data = data
            self.next = None
    
    
    def __init__(self):
        self.head = linked_list.node()
        
    def append(self, data):
        new_node = linked_list.node(data)
        cur = self.head
        while cur.next != None:
            cur = cur.next
        cur.next = new_node

Answer 2

如果要將節點 class 保留在鏈接列表 class 中，則需要從鏈接列表 ZA2F2ED4F8EBC2B61DZC 中調用節點 class。 所以要做到這一點，你必須做new_node = linked_list.node(data) 。 Rest 都應該一樣