1. 实例: 下载一首英文的歌词或文章，将所有,.？！等替换为空格，将所有大写转换为小写，统计某几个单词出现的次数，分隔出一个一个的单词。
   a = '''God Is A GirlRemembering me, Discover and see All over the world, She's known as a girl To those who a free, The mind shall be key Forgotten as the past 'Cause history will last God is a girl, Wherever you are, Do you believe it, can you recieve it? God is a girl, Whatever you say, Do you believe it, can you recieve it? God is a girl, However you live, Do you believe it, can you recieve it? God is a girl, She's only a girl, Do you believe it, can you recieve it? She wants to shine, Forever in time, She is so driven, she's always mine Cleanly and free, She wants you to be A part of the future, A girl like me There is a sky, Illuminating us, someone is out there That we truly trust There is a rainbow for you and me A beautiful sunrise ete'''a =a.lower()print('god出现次数为：'+str(a.count('god')))for i in ',','?','!':    a=a.replace(i,' ')a=a.split(' ')print(a)

    

    

2. 列表实例：由字符串创建一个作业评分列表，做增删改查询统计遍历操作。例如，查询第一个3分的下标，统计1分的同学有多少个，3分的同学有多少个等。
   grade=list('12312133212321')grade=[int(x) for x in grade]print('成绩表：',grade)grade.insert(0,2)print('开始增加分值为2的分数',grade)grade.pop(0)print('删除增加的分数',grade)print('输出第一个3分的同学的下标:',grade.index(3))print('统计1分的同学人数:',grade.count(1))print('统计3分的同学人数:',grade.count(3))

   

    

3. 简要描述列表与元组的异同。                                                                           
4. 列表是可变的数据类型，用方括号显示。元组是不可变的 ，用圆括号显示。两者都可以嵌套。