python 实现线性链表（单链表）

转载：https://blog.csdn.net/King0217/article/details/78228433

# -*- coding:utf-8 -*-


# 结点类，
class Node:

    def __init__(self, data):
        self.data = data            # 数据域
        self.next = None            # 指针域

    def get_data(self):
        return self.data


# 链表类
class List:

    def __init__(self, head):
        self.head = head            # 默认初始化头结点

    def is_empty(self):         # 空链表判断
        return self.get_len() == 0

    def get_len(self):          # 返回链表长度
        length = 0
        temp = self.head
        while temp is not None:
            length += 1
            temp = temp.next
        return length

    def append(self, node):         # 追加结点（链表尾部追加）
        temp = self.head
        while temp.next is not None:
            temp = temp.next
        temp.next = node

    def delete(self, index):           # 删除结点
        if index < 1 or index > self.get_len():
            print "给定位置不合理"
            return
        if index == 1:
            self.head = self.head.next
            return
        temp = self.head
        cur_pos = 0
        while temp is not None:
            cur_pos += 1
            if cur_pos == index-1:
                temp.next = temp.next.next
            temp = temp.next

    def insert(self, pos, node):         # 插入结点
        if pos < 1 or pos > self.get_len():
            print "插入结点位置不合理..."
            return
        temp = self.head
        cur_pos = 0
        while temp is not Node:
            cur_pos += 1
            if cur_pos == pos-1:
                node.next = temp.next
                temp.next =node
                break
            temp = temp.next

    def reverse(self, head):          # 反转链表
        if head is None and head.next is None:
            return head
        pre = head
        cur = head.next
        while cur is not None:
            temp = cur.next
            cur.next = pre
            pre = cur
            cur = temp
        head.next = None
        return pre

    def print_list(self, head):           # 打印链表
        init_data = []
        while head is not None:
            init_data.append(head.get_data())
            head = head.next
        return init_data


if __name__ == '__main__':

    head = Node("head")
    list = List(head)
    print '初始化头结点：\t', list.print_list(head)

    for i in range(1, 10):
        node = Node(i)
        list.append(node)
    print '链表添加元素：\t', list.print_list(head)

    print '链表是否空：\t', list.is_empty()

    print '链表长度：\t', list.get_len()

    list.delete(9)
    print '删除第9个元素:\t',list.print_list(head)

    node = Node("insert")
    list.insert(3, node)
    print '第3个位置插入‘insert’字符串 :\t', list.print_list(head)

    head = list.reverse(head)
    print '链表反转：', list.print_list(head)

执行结果：