python中的单向链表实现

class node:
    def __init__(self,data):
        self.data = data #节点的值域
        self.next = None #连接下一个节点，暂时指向空

class linkList:
    def __init__(self):
        self.head = None #首先建立链表头，暂时指向空

    #判断链表是否为空
    def isEmpty(self):
        if self.head:
            return False
        else:
            return True

    def length(self):
        if self.isEmpty():
            return 0
        else:
            t = self.head
            n = 1
            while t.next:
                t = t.next
                n = n + 1
            return n

    def addhead(self,data):
        node = Node(data) #新建一个节点
        node.next = self.head #新建的节点接上原来的链表
        self.head = node #重置链表的头

    def addtail(self,data):
        node = Node(data) #新建一个节点
        #先判断链表是否为空
        if self.isEmpty():
            self.addhead(data)
        else:
            t = self.head 
            while t.next: #通过循环找到尾部
                t = t.next 
            t.next = node #尾部接上

    def insert(self,data,index):
        if index == 0 or self.isEmpty():
            self.addhead(data)
        elif index >= self.length():
            self.addtail(data)
        else:
            node = Node(data)
            t = self.head
            n = 1
            while n < index - 1:
                t = t.next
                n = n + 1
            a = t.next.next
            t.next = node
            node.next = a

    def delete(self,index):
        if self.isEmpty():
            print("The linked list is empty")
        else:
            t = self.head
            if index == 0:
                self.head = t.next
            elif index == self.length() - 1:
                n = 1
                while n < self.length() - 1:
                    t = t.next
                    n = n + 1
                t.next = None
            elif index > self.length() - 1:
                print("Out of range")
            elif index < 0:
                print("Wrong operation")
            else:
                n = 1
                while n < index - 1:
                    t = t.next
                    n = n + 1
                a = t.next.next
                t.next = a

    def search(self,data):
        t = self.head
        n = 1
        while t.next:
            if t.data == data:
                print(str(n) + " ")
            t = t.next
            n = n + 1
        if (t.data == data):
            print(str(n) + " ")

    def fORM(self,datalist):
        self.addhead(datalist[0])
        for i in range(1,len(datalist)):
            self.addtail(datalist[i])
        t = self.head
        while t.next:
            print(t.data)
            t = t.next
        print(t.data)

    def form(self,datalist):
        self.addhead(datalist[0])
        for i in range(1,len(datalist)):
            self.addtail(datalist[i])
        t = self.head
        while t.next:
            print(t.data)
            t = t.next
        print(t.data)

data = input("input(以空格为界):")
data = data.split(" ")
linkList = linkList()
linkList.form(data) #创建链表
addlist = linkList.addhead(5) #在头节点加入
linkList.erGodic() #遍历输出
addlist = linkList.addtail(5) #在尾节点加入
linkList.ergodic() #遍历输出
linkList.search(5) #查找是否有"5"的节点
linkList.delete(4) #删除第4个数据
linkList.ergodic() #遍历输出
print(linkList.length()) #输出链表长度
linkList.insert(89,2) #指定位置插入数据
linkList.ergodic() #遍历输出