数据结构-顺序表的定义及python实现

class SeqList(object):
    def __init__(self,size=50):  # 初始化线性表
        # 定义线性表的最大长度为50
        self.max=size
        self.num=0
        self.data=[None]*self.max
    def is_empty(self): # 判断线性表是否为空
        return self.num is 0
    def if_full(self): # 判断线性表是否为满
        return self.num is self.max
    def __getitem__(self, index): # 获取线性表中某一位置的值
        if not isinstance(index,int):
            raise TypeError
        if 0 <= index < self.max:
            return self.data[index]
        else:
            raise IndexError
    def __setitem__(self, index, value): # 修改线性表中某一位置的值
        if not isinstance(index,int):
            raise TypeError
        if 0<=index<self.max:
            self.data[index]=value
        else:
            raise IndexError
    def locate_item(self,value):  # 按值查找第一个等于该值的索引
        for i in range(self.num):
            if self.data[i]==value:
                return i
        return -1
    def count(self):  # 返回线性表中元素的个数
        return self.num
    def append_last(self,value):  # 在表尾插入一个元素
        if self.num>self.max:
            print("list is full")
        else:
            self.data[self.num]=value
            self.num+=1
    def insert(self,index,value):  # 在表中任意位置插入一个元素
        if self.num>=self.max:
            print("list is full")
        if not isinstance(index,int):
            raise TypeError
        if index<0 or index>self.num:
            raise IndexError
        for i in range(self.num,index,-1):
            self.data[i]=self.data[i-1]
        self.data[index]=value
        self.num += 1
    # def insert_by_loc(self,i,value):  # 在线性表的第i个位置插入值value  表头 表中 表尾 都可以
    #     if i < 1 or i > self.num+1:
    #         print("i is not right")
    #     if self.num >= self.max:
    #         print("list is full!")
    #     for j in range(self.num+1,i,-1):
    #         self.data[j]=self.data[j-1]
    #     self.data[i-1]=value
    #     self.num += 1
    def remove(self,index):  # 删除表中某一位置的值
        if isinstance(index,int):
            raise TypeError
        if index < 0 or index >= self.num:
            raise IndexError
        for i in range(index,self.num):
            self.data[i]=self.data[i+1]
        self.num -= 1
    def print_list(self): # 删除线性表
        for i in range(0,self.num):
            print(self.data[i])
    def destroy(self): # 销毁线性表
        self.__init__()
if __name__ == '__main__':
    seqlist=SeqList()
    print(seqlist.is_empty())
    seqlist.append_last(18)
    print(seqlist.__getitem__(0))