Python implements singly linked list

# coding:utf-8 


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


class LinkList: 
    def __init__(self, data=[0]): 
        self.head = None 
        self.init_link_list(data) 

    # 初始化链表 
    # data 为数组 
    def init_link_list(self, data): 
        if len(data) == 0: 
            print("Initialization data is null") 
            return 
        self.head = Node(data[0]) 
        current = self.head 
        for index in data[1:]: 
            current.next = Node(index) 
            current = current.next 

    # 获取当前结点 
    def get_node(self, index): 
        if self.is_empty(): 
            print("link is empty") 
            return 
        if index > self.get_length() or index <= 0: 
            print("node is not exist") 
            return 
        current = self.head 
        i = 0 
        while i < index: 
            if i == index - 1: 
                return current 
            current = current.next 
            i += 1 

    # 获取当前元素的值 
    def get_data(self, index): 
        current = self.get_node(index) 
        if current is None: 
            return "node is not exist" 
        return current.data 

    # 打印链表 
    def print_link(self): 
        if self.is_empty(): 
            return 
        list = [] 
        current = self.head 
        while current.next is not None: 
            list.append(current.data) 
            current = current.next 
        else: 
            list.append(current.data) 
        print(list) 

    # 获取链表长度 
    def get_length(self): 
        if self.is_empty(): 
            return 0 
        current = self.head 
        count = 0 
        while current.next is not None: 
            count += 1 
            current = current.next 
        else: 
            count += 1 
        return count 

    # 判断链表是否为空 
# If it is empty, return true
# If not empty, return false def is_empty(self):
return self.head is None

# Insert an element after the current element
# index element index
# data Inserted value
      def add_after(self, index, data):                                                                                                                                                                                                                                                                                   de(data)
current = current.next
            current.next                                                           use           use ’s ’ using ’s ’ using ’s out through using ‐‐‐ ‐‐‐‐ together to self .head = Node(data)                                                                                                                                                                           . Pre = pre.next
Pre. next = current

      # Get the previous element of the current element            def get_pre_node(self, index)                                                                                                        gt; self.get_length( ) or index <= 1:
 == index - 2:
                                                                                                             pre = pre.next
i += 1

# Delete the specified element, and return the value of the delete element
DEF Remove (SELF, Index):
IF Index == 1 and not self.is_empty ():
Data = Self .head.data
                                                                                                                                                                                                                                                                     . :
                                                                                                print("data is not exist")
                                                                                                                                                    Is None: t Return "Current Node is None"
Current.data = Data

# merged the new linked list to the current linked list
DEF MERGE (SELF, DATA):
        size = self.get_length() 
        last_node = self.get_node(size) 
        last_node.next = data.head 
        return self 

# test 
y = (1,2,3,4) 
s = ["a", "b", "c", "d"] 
linkList = LinkList(y) 
# linkList.init_link_list(["a", "b", "c", "d"]) 
# second = LinkList() 
# second.init_link_list(["x", "y", "z"]) 
# linkList.add_after(-1, "x") 
# linkList.add_after(1, "y") 
# linkList.init_link_list([]) 
# linkList.add_before(1,"x") 
# linkList.print_link() 
# print("item:", linkList.get_data(2)) 
# print("length:", linkList.get_length()) 
# print("is empty", linkList.is_empty()) 
# print(linkList.get_pre_node(3).data) 
# print("remove node:",linkList.remove(2)) 
# linkList.merge(second) 


linkList.print_link()