如何同时遍历两个文件中的行?
问题描述
我有两个文件,我想对它们执行一些逐行操作.(换句话说,每个文件的第一行是对应的,第二行也是如此,等等.)现在,我可以想到一些稍微麻烦的方法来同时遍历两个文件.然而,这是 Python,所以我想有一些语法简写.
I have two files, and I want to perform some line-wise operation across both of them. (In other words, the first lines of each file correspond, as do the second, etc.) Now, I can think of a number of slightly cumbersome ways to iterate across both files simultaneously; however, this is Python, so I imagine that there is some syntactic shorthand.
换句话说,有没有一些简单的方法来适应
In other words, is there some simple way to adapt the
for line in file:
以便同时从两个文件中提取数据?
so that it pulls data from both files simultaneously?
解决方案
Python 2:
使用 itertools.izip
加入两个迭代器.
Use itertools.izip
to join the two iterators.
from itertools import izip
for line_from_file_1, line_from_file_2 in izip(open(file_1), open(file_2)):
如果文件长度不等,请使用 izip_longest
.
If the files are of unequal length, use izip_longest
.
在 Python 3 中,请改用 zip
和 zip_longest
.此外,使用 with
打开文件,这样即使出现错误,也会自动处理关闭.
In Python 3, use zip
and zip_longest
instead. Also, use a with
to open files, so that closing is handled automatically even in case of errors.
with open(file1name) as file1, open(file2name) as file2:
for line1, line2 in zip(file1, file2):
#do stuff
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