文件操作

name1='李子'
name2='郑子'
classmates=['李子','郑j子','橘bb子',1]
print(name1,classmates[-1],len(classmates))
classmates.append('ring')
classmates.insert(1,'果子')
print(classmates)
classmates.pop()
classmates.pop(1)
classmates[1]='桑果'
print(classmates)

fr = open('plainText.txt',mode='r',encoding='utf-8')
plainText = fr.read()
print(plainText)
print('密文：',end='')
for c in plainText:
    print(chr(ord(c)+3),end='')


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