Python的with open file as 自我了解解释

#!/usr/bin/env python
# -*- coding:utf-8 -*-
with open ('1.txt') as f1:
    f1.line = f1.readlines()
    print (f1.line)

with  open('2.txt') as f2:
    f2.line = f2.readlines()
    print (f2.line)

#写在一块  中间用，分开，注意最后:结尾，     类似循环语句的结尾
with open ('1.txt') as f1,open('2.txt') as f2:
    f1.line = f1.readlines()
    f2.line = f2.readlines()
    print (f1.line)
    print (f2.line)