#!/usr/bin/env python

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

 class SeqList(object):

     def __init__(self, max=8):

         self.max = max      #创建默认为8

         self.num = 0

         self.date = [None] * self.max

         #list()会默认创建八个元素大小的列表，num=0，并有链接关系

         #用list实现list有些荒谬，全当练习

         #self.last = len(self.date)

         #当列表满时，扩建的方式省略

     def is_empty(self):

         return self.num is 0

     def is_full(self):

         return self.num is self.max

     #获取某个位置的元素

     def __getitem__(self, key):

         if not isinstance(key, int):

             raise TypeError

         if 0<= key < self.num:

             return self.date[key]

         else:

             #表为空或者索引超出范围都会引发索引错误

             raise IndexError

     #设置某个位置的元素

     def __setitem__(self, key, value):

         if not isinstance(key, int):

             raise TypeError

         #只能访问列表里已有的元素,self.num=0时，一个都不能访问,self.num=1时，只能访问0

         if 0<= key < self.num:

             self.date[key] = value   #该位置无元素会发生错误

         else:

             raise IndexError

     def clear(self):

         self.__init__()

     def count(self):

         return self.num

     def __len__(self):

         return self.num

     #加入元素的方法 append()和insert()

     def append(self,value):

         if self.is_full():

             #等下扩建列表

             print("list is full")

             return

         else:

             self.date[self.num] = value

             self.num += 1

     def insert(self,key,value):

         if not isinstance(key, int):

             raise TypeError

         if key<0:  #暂时不考虑负数索引

             raise IndexError

         #当key大于元素个数时，默认尾部插入

         if key>=self.num:

             self.append(value)

         else:

             #移动key后的元素

             for i in range(self.num, key, -1):

                 self.date[i] = self.date[i-1]

             #赋值

             self.date[key] = value

             self.num += 1

     #删除元素的操作

     def pop(self,key=-1):

         if not isinstance(key, int):

             raise   TypeError

         if self.num-1 < 0:

             raise IndexError("pop from empty list")

         elif key == -1:

             #原来的数还在，但列表不识别他

             self.num -= 1

         else:

             for i in range(key,self.num-1):

                 self.date[i] = self.date[i+1]

             self.num -= 1

     def index(self,value,start=0):

         for i in range(start, self.num):

             if self.date[i] == value:

                 return i

         #没找到

         raise ValueError("%d is not in the list" % value)

     #列表反转

     def reverse(self):

         i,j = 0, self.num - 1

         while i<j:

             self.date[i], self.date[j] = self.date[j], self.date[i]

             i,j = i+1, j-1

 if __name__=="__main__":

     a = SeqList()

     print(a.date)

     #num == 0

     print(a.is_empty())

     a.append(0)

     a.append(1)

     a.append(2)

     print(a.date)

     print(a.num)

     print(a.max)

     a.insert(1,6)

     print(a.date)

     a[1] = 5

     print(a.date)

     print(a.count())

     print("返回值为2(第一次出现)的索引：", a.index(2, 1))

     print("====")

     t = 1

     if t:

         a.pop(1)

         print(a.date)

         print(a.num)

     else:

         a.pop()

         print(a.date)

         print(a.num)

     print("========")

     print(len(a))

     a.reverse()

     print(a.date)

     """

     print(a.is_full())

     a.clear()

     print(a.date)

     print(a.count())

     """