Python3单链表简单操作

class Node():
    # 定义头结点
    def __init__(self, data):
        self.data = data
        # 头指针为空
        self.next = None


# 头插法
class SNode():
    def __init__(self):
        self.current_node = None

    def add_node(self, data):
        node = Node(data)
        node.next = self.current_node
        self.current_node = node

    def append_node(self, data):
        # 尾插法插入节点
        node = Node(data)
        cur = self.current_node
        # 遍历链表直到头节点处停止遍历
        while cur:
            if cur.next == None:
                break
            cur = cur.next
        cur.next = node

    def travel(self):
        '''
        遍历链表
        :return:
        '''
        cur = self.current_node
        while cur:
            print(cur.data)
            cur = cur.next

    def is_empty(self):
        '''
        判断链表非空
        :return:
        '''
        return self.current_node == None

    def get_lenth(self):
        '''
        获取链表的长度
        :return:
        '''
        cur = self.current_node
        count = 0
        while cur:
            count += 1
            cur = cur.next
        return count

    def insert_node(self, index, data):
        '''
        指定位置插入节点
        :param index:
        :param data:
        :return:
        '''
        link_len = self.get_lenth()
        if index == 0:
            self.add_node(data)
        elif index >= link_len:
            self.append_node(data)
        else:
            cur = self.current_node
            for i in range(1, index):
                cur = cur.next
            node = Node(data)
            node.next = cur.next
            cur.next = node

    def del_node(self, index):
        '''
        根据索引删除节点
        :param index:
        :return:
        '''

        # 找到前节点
        cur = self.current_node
        # 前驱节点
        pre = None
        count = 1
        len_num = self.get_lenth()
        while cur:
            if index == 1:
                self.current_node = cur.next
                break
            if count == index and count = len_num:
                pre.next = None
                break
            count += 1
            pre = cur
            cur = cur.next



if __name__ == "__main__":
    test = SNode()
    list_data = [1, 2, 3]
    for i in list_data:
        test.add_node(i)
    test.travel()
    # print(test.is_empty())
    # print (test.get_lenth())
    # test.append_node(4)
    # test.insert_node(1, 4)
    # test.travel()
    # test.del_node(4)
    # test.travel()

    '''
    单链表的操作
is_empty() 链表是否为空
length() 链表长度
travel() 遍历整个链表
add(item) 链表头部添加元素
append(item) 链表尾部添加元素
insert(pos, item) 指定位置添加元素
remove(item) 删除节点
search(item) 查找节点是否存在
    '''