哪个 dunder 方法 (method) 可以复制自定义数据对象中的 del obj[index]？

Question

我只是在尝试使用链表的混合模型进行一些修改。我已经实现了 object.delete_node(index)，它只是 link 下一个节点，因为它在 vanilla 链表中。现在，想要实现与 object.delete_node(index) 功能相同的 del object[index]。我该如何实施？它在 list 中实现，在 Python 中实现 dict。哪个方法负责相同？

下面是我的 LinkedList 的代码，效果很好。

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

    def __str__(self):
        return self.__repr__()
    
    def __repr__(self):
        return str(self.data)


class LinkedList:
    def __init__(self):
        self.head = Node()
        self.length = 0

    def insert_node(self, data):
        new_node = Node(data) # node to be inserted
        current_node = self.head
        while current_node.next_pointer != None: # it'll only stop at the last node which is obviously empty
            current_node = current_node.next_pointer # bring out next pointer
        current_node.next_pointer = new_node

        self.length += 1


    def delete_node(self, index):
        if self.length == 0: raise ValueError(f"Can not delete from empty Linked List")
        if (index > self.length - 1) or (index < -self.length -1): raise ValueError(f"index {index} out of bounds of max length")
        if index < 0: index = self.length + index

        count = 0
        current_node = self.head
        while count < index:
            current_node = current_node.next_pointer
            count += 1

        current_node.next_pointer = current_node.next_pointer.next_pointer if current_node.next_pointer.next_pointer != None else None
        self.length -= 1


    def _slice_return(self, slice_index):
        '''
        Implement slicing Operation just like in Python Lists and Strings
        '''
        index = slice_index.start
        stop = min(slice_index.stop, self.length -1)
        step = 1 if slice_index.step == None else slice_index.step

        if index < 0: raise NotImplementedError("Negative slicing not implemented")

        if (index > self.length - 1) or (index < -self.length -1): raise ValueError(f"index {index} out of bounds of max length")
        if index < 0: index = self.length + index

        ll = LinkedList()
        for i in range(index, stop,step):
            ll.insert_node(self[i].data)
        return ll


    def __getitem__(self, index):
        if isinstance(index, slice):
            return self._slice_return(index)
            
        if (index > self.length - 1) or (index < -self.length -1): raise ValueError(f"index {index} out of bounds of max length")
        if index < 0: index = self.length + index
        
        count = 0
        current_node = self.head.next_pointer
        while count != index:
            current_node = current_node.next_pointer
            count += 1
        
        return current_node


    def __len__(self):
        return self.length
    

    def __str__(self):
        array = []
        node = self.head
        count = self.length
        while count > 0:
            node = node.next_pointer
            array.append(node.data)
            count -= 1
            
        return(str(array))

    def __repr__(self):
        return self.__str__()


ll = LinkedList()
ll.insert_node("a")
ll.insert_node("b")
ll.insert_node("A")
ll.insert_node("B")

ll.delete_node(2) # delete 3rd node

Answer 1

基于@jonrsharpe 评论的回答：

python 文档中有一个 Datamodel 部分，其中包含可用的 dunder 方法列表

你的情况是：

object.__delitem__(self, key)

Called to implement deletion of self[key]. Same note as for __getitem__(). This should only be implemented for mappings if the objects support removal of keys, or for sequences if elements can be removed from the sequence. The same exceptions should be raised for improper key values as for the __getitem__() method.

哪个 dunder 方法 (method) 可以复制自定义数据对象中的 del obj[index]？

Which dunder method (method) can replicate del obj[index] in custom data objects?

python

linked-list

data-structures

python-3.x

哪个 dunder 方法 (__method__) 可以复制自定义数据对象中的 del obj[index]？

Which dunder method (__method__) can replicate del obj[index] in custom data objects?

python

linked-list

data-structures

python-3.x

哪个 dunder 方法 (method) 可以复制自定义数据对象中的 del obj[index]？

Which dunder method (method) can replicate del obj[index] in custom data objects?