1、打开cmd

2、进入python交互界面

3、定义字符串 str = 'this is a test'

4、将字符串全部大写 upStr = str.upper(),并打印

5、将upStr装换成小写 loStr = upStr.lower()

1、1.打开cmd
2.进入python交互界面
3.定义字符串 str = 'this is a test'
4.将字符串全部大写 upStr = str.upper(),并打印
5.将upStr装换成小写 loStr = upStr.lower()