Python中的"with"语句,需要处理多个文件

Question

在这种情况下如何使用with语句？

f_spam = open(spam,'r')
f_bar = open(eggs,'r')
...
do something with these files
...
f_spam.close()
f_bar.close()

文件编号可能大于2.

Answer 1

你也可以这样做:

from contextlib import nested

with nested(open(spam), open(eggs)) as (f_spam, f_eggs):
    # do something

在Python 2.7和3.1+中,您不需要该nested函数,因为它with支持以下语法:

with open(spam) as f_spam, open(eggs) as f_eggs:
    # do something