name1 = 'gaga'name2 = 'katherine'classmates = ['gaga','katherine','lily','luckly']classmates.append('coco')classmates.insert(1,'cole')classmates.pop()classmates.pop(4)classmates[0] = 'jingyi'print(len(classmates),classmates)

 

name1 = 'gaga'name2 = 'katherine'classmates = ['gaga','katherine','lily','luckly']classmates.append('coco')classmates.insert(1,'cole')classmates.pop()classmates.pop(4)print(len(classmates),classmates)

 

name1 = 'gaga'name2 = 'katherine'classmates = ['gaga','katherine','lily','luckly']classmates.append('coco')classmates.insert(1,'cole')classmates.pop()print(len(classmates),classmates)

 

name1 = 'gaga'name2 = 'katherine'classmates = ['gaga','katherine','lily','luckly']classmates.append('coco')classmates.insert(1,'cole')print(len(classmates),classmates)

 

name1 = 'gaga'name2 = 'katherine'classmates = ['gaga','katherine','lily','luckly']classmates.append('coco')print(len(classmates),classmates)

 

 

fr = open('gaga.txt',mode='r',encoding='utf-8')gaga = fr.read()print('明文：'+gaga)print('密文：',end='')fw = open('cipherText.txt',mode='a',encoding='utf-8')for c in gaga:    print(chr(ord(c)+3),end='')    fw.write(chr(ord(c)+3))fr.close()fw.close()

 

 

 

fr = open('gaga.txt',mode='r',encoding='utf-8')gaga = fr.read()print('明文：'+gaga)print('密文：',end='')fw = open('cipherText.txt',mode='a',encoding='utf-8')for c in gaga:    print(chr(ord(c)-3),end='')    fw.write(chr(ord(c)-3))fr.close()fw.close()