python实现数据结构中链表的代码

下面是 Python 实现单向链表的代码：

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

class LinkedList:
    def __init__(self):
        self.head = None
        
    def append(self, data):
        new_node = Node(data)
        if self.head is None:
            self.head = new_node
            return
        last_node = self.head
        while last_node.next:
            last_node = last_node.next
        last_node.next = new_node
        
    def prepend(self, data):
        new_node = Node(data)
        new_node.next = self.head
        self.head = new_node
        
    def insert_after_node(self, prev_node, data):
        if not prev_node:
            print("Previous node is not in the list")
            return
        new_node = Node(data)
        new_node.next = prev_node.next
        prev_node.next = new_node
        
    def delete_node(self, key):
        curr_node = self.head
        if curr_node and curr_node.data == key:
            self.head = curr_node.next
            curr_node = None
            return
        prev_node = None
        while curr_node and curr_node.data != key:
            prev_node = curr_node
            curr_node = curr_node.next
        if curr_node is None:
            return
        prev_node.next = curr_node.next
        curr_node = None
        
    def print_list(self):
        curr_node = self.head
        while curr_node:
            print(curr_node.data)
            curr_node = curr_node.next

上述代码实现了链表的基本操作，包括添加节点、插入节点、删除节点以及打印链表。你可以通过下面的代码测试上述代码：

linked_list = LinkedList()
linked_list.append("A")
linked_list.append("B")
linked_list.append("C")
linked_list.prepend("D")
linked_list.insert_after_node(linked_list.head.next, "E")
linked_list.delete_node("B")
linked_list.print_list() #输出 D A E C