链表实现python list数据类型

#1.<--用单链表的数据结构实现列表
class error(Exception):
    def __init__(self,msg):
        super(error,self).__init__(self)
        self.mes=msg
    def __str__(self):
        return self.mes

class Node():
    def __init__(self,val=None):
        self.val=val
        self.next=None
class MyList():
    def __init__(self,ele=None):
        self._head=ele
    #空数组
    def empty(self):
        return self._head==None
    #在头部添加
    def add(self,ele):
        node=Node(ele)
        node.next=self._head
        self._head=node
    #测数组的长度
    def length(self):
        num=0
        cursor=self._head
        while cursor!=None:
            cursor = cursor.next
            num+=1
        return num
    #获取指定下标的元素
    def get(self,index):
        if index<0 or index>self.length()-1:
            raise error("Index is outside the range of range")
        else:
            cursor = self._head
            num=0
            while num<index+1:
                if num==index:
                    return cursor.val
                cursor = cursor.next
                num+=1
    #在最后添加一个元素
    def append(self,ele):
        node = Node(ele)
        if self.empty():
            self._head=node
        else:
            cursor = self._head
            while cursor.next!=None:
                cursor = cursor.next
            cursor.next=node
    #在指定位置插入一个元素
    def insert(self,index,ele):
        if index<0 or index>self.length():
            raise error("Index is outside the range of range")
        else:
            if index==0:
                self.add(ele)
            elif index==self.length():
                self.append(ele)
            else:
                node = Node(ele)
                cursor = self._head
                num=0
                while num<index:
                    if num==index-1:
                        node.next = cursor.next
                        cursor.next = node
                    cursor = cursor.next
                    num+=1
    #弹出最后一个元素
    def pop(self):
        if self.empty():
            return None
        else:
            if self.length()==1:
                item=self._head.val
                self._head=None
                return item
            else:
                cursor=self._head
                pre=None
                while cursor.next!=None:
                    pre=cursor
                    cursor=cursor.next
                ele=cursor.val
                pre.next=None
                return ele
    #删除第一个匹配内容的元素
    def remove(self,num):
        if self.empty():
            return None
        elif self.length()==1:
            pre=self._head
            self._head=None
            return pre.val
        else:
            cursor=self._head
            pre=None
            while cursor.val!=num:
                pre=cursor
                cursor=cursor.next
            if pre==None:
                pre=self._head
                self._head=pre.next
                return pre.val
            elif cursor.next!=None:
                pre.next=cursor.next
                return cursor.val
            else:
                pre.next=None
                return cursor.val
    #删除指定下标的元素
    def delete(self,index):
        if self.length()==1:
            pre=self._head
            self._head=None
            return pre.val
        else:
            cursor=self._head
            num=0
            pre=None
            while num<index and cursor.next!=None:
                pre=cursor
                cursor=cursor.next
                num+=1
            if pre==None:
                pre = self._head
                self._head = pre.next
                return pre.val
            elif cursor.next!=None:
                pre.next=cursor.next
                return cursor.val
            else:
                pre.next=None
                return cursor.val
    #下两个函数时制作迭代器的
    def __iter__(self):
        return self
    def __next__(self):
        num=0
        if self._head==None:
            raise StopIteration
        else:
            pre=self._head.val
            self._head=self._head.next
            return pre

list2=MyList()
list2.add("a")
list2.append("b")
list2.insert(1,"h")
list2.insert(1,"11")

for item in list2:
    print(item,end=" ")

#2.<--用单向循环链表的数据结构实现列表
class error(Exception):
    def __init__(self,msg):
        super(error,self).__init__()
        self.err=msg
    def __str__(self):
        return self.err
class Node():
    def __init__(self,val=None):
        self.val=val
        self.next=None

class MyList():
    def __init__(self,ele=None):
        self._head=ele
        self.count = 0
    def empty(self):
        return self._head==None
    def add(self,ele):
        if self.empty():
            node = Node(ele)
            self._head=node
            self._head.next=self._head
        else:
            node=Node(ele)
            cursor=self._head
            while cursor.next!=self._head:
                cursor=cursor.next
            node.next=self._head
            self._head=node
            cursor.next=self._head
    def length(self):
        if self.empty():
            return 0
        else:
            cursor=self._head
            num=1
            while cursor.next!=self._head:
                num+=1
                cursor=cursor.next
            return num
    def get(self,index):
        if index<0 or index>self.length()-1:
            raise error("Index exceeds the length of rang")
        else:
            cursor = self._head
            num=0
            while num<index+1:
                if num==index:
                    return cursor.val
                cursor=cursor.next
                num+=1
    def appen(self,ele):
        if self.empty():
            node=Node(ele)
            self._head=next()
            self._head.next=self._head
        else:
            node = Node(ele)
            cursor=self._head
            while cursor.next!=self._head:
                cursor=cursor.next
            cursor.next=node
            node.next=self._head
    def pop(self):
        if self.length()==1:
            pre=self._head
            self._head=None
            return pre.val
        else:
            cursor=self._head
            pre=None
            while cursor.next!=self._head:
                pre=cursor
                cursor=cursor.next
            pre.next=cursor.next
            return cursor.val
    def __iter__(self):
        return self
    def __next__(self):
        cursor=self._head
        if self.count<self.length():
            num=0
            while num<self.count:
                num+=1
                cursor=cursor.next
            self.count+=1
            return cursor.val
        else:
            raise StopIteration

mlist=MyList()
mlist.add("a")
mlist.add("b")
mlist.add("c")
mlist.appen(1)
mlist.appen("h")

#print(mlist.empty())
print(mlist.length())
# print(mlist.get(0),end=" ")
# print(mlist.get(1),end=" ")
# print(mlist.get(2),end=" ")
# print(mlist.get(3),end=" ")
# print(mlist.get(4),end=" ")
for item in mlist:
    print(item,end=" ")

#3.<--用双向链表的数据结构实现列表
class error(Exception):
    def __init__(self,msg):
        super(error,self).__init__()
        self.err=msg
    def __str__(self):
        return self.err
class Node():
    def __init__(self,val=None):
        self.val=val
        self.next=None
        self.last=None
class MyList():
    def __init__(self,ele=None):
        self._head=ele
        self.count=0
    def empty(self):
        return self._head==None
    def add(self,ele):
        if self.empty():
            node=Node(ele)
            self._head=node
        else:
            node = Node(ele)
            pre=self._head
            self._head=node
            node.next=pre
            pre.last=self._head
    def length(self):
        if self.empty():
            return 0
        else:
            cursor=self._head
            num=1
            while cursor.next!=None:
                cursor=cursor.next
                num += 1
            return num
    def get(self,index):
        if index<0 or index>self.length()-1:
            raise error("Index exceeds the length of rang")
        else:
            cursor=self._head
            num=0
            while num<index+1:
                if num==index:
                    return cursor.val
                cursor=cursor.next
                num+=1
            return num
    def append(self,ele):
        if self.empty():
            node=Node(ele)
            self._head=node
        else:
            node = Node(ele)
            cursor = self._head
            while cursor.next !=None:
                cursor=cursor.next
            cursor.next=node
            node.last=cursor
    def pop(self):
        if self.empty():
            return None
        else:
            if self.length()==1:
                pre=self._head
                self._head=None
                return pre.val
            else:
                cursor=self._head
                pre=None
                while cursor.next!=None:
                    pre=cursor
                    cursor=cursor.next
                pre.next=None
    def __iter__(self):
        return self
    def __next__(self):
        cursor = self._head
        if self.count < self.length():
            num = 0
            while num < self.count:
                num += 1
                cursor = cursor.next
            self.count += 1
            return cursor.val
        else:
            raise StopIteration

        # if self._head.next==None:
        #     raise StopIteration
        # else:
        #     val=self._head.val
        #     self._head=self._head.next
        #     self._head.last=None
        #     return val

arr=MyList()
arr.add("a")
arr.add("b")
arr.add("c")
arr.append("1")
arr.append("d")
arr.append("f")
arr.pop()
arr.pop()
arr.pop()

# print(arr.empty())
# print(arr.length())
# print(arr.get(0),end=" ")
# print(arr.get(1),end=" ")
# print(arr.get(2),end=" ")
# print(arr.get(3),end=" ")
# print(arr.get(4),end=" ")
# print(arr.get(5),end=" ")
for item in arr:
    print(item,end=" ")