本文介绍了用grep表示一个单词,如果找到,则在模式匹配前打印10行,在模式匹配后打印10行的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在处理一个巨大的文件.我想在该行中搜索一个单词,找到后我应该在模式匹配之前打印10行,在模式匹配之后打印10行.如何在Python中做到这一点?
I am processing a huge file. I want to search for a word in the line and when found I should print 10 lines before and 10 lines after the pattern match. How can I do it in Python?
推荐答案
import collections
import itertools
import sys
with open('huge-file') as f:
before = collections.deque(maxlen=10)
for line in f:
if 'word' in line:
sys.stdout.writelines(before)
sys.stdout.write(line)
sys.stdout.writelines(itertools.islice(f, 10))
break
before.append(line)
使用 collections.deque
最多保存10行匹配之前,然后 itertools.islice
即可获得下一行比赛.
used collections.deque
to save up to 10 lines before match, and itertools.islice
to get next 10 lines after the match.
更新要排除具有ip/mac地址的行:
UPDATE To exclude lines with ip/mac address:
import collections
import itertools
import re # <---
import sys
addr_pattern = re.compile(
r'\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b|'
r'\b[\da-f]{2}:[\da-f]{2}:[\da-f]{2}:[\da-f]{2}:[\da-f]{2}:[\da-f]{2}\b',
flags=re.IGNORECASE
) # <--
with open('huge-file') as f:
before = collections.deque(maxlen=10)
for line in f:
if addr_pattern.search(line): # <---
continue # <---
if 'word' in line:
sys.stdout.writelines(before)
sys.stdout.write(line)
sys.stdout.writelines(itertools.islice(f, 10))
break
before.append(line)
这篇关于用grep表示一个单词,如果找到,则在模式匹配前打印10行,在模式匹配后打印10行的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!