[英]Use python to grep lines from one file out of another file
Similar question to alternative of "grep" in python; 类似的问题替代python中的“grep”; but the complexity here is what is grepped is variable (lines) from another file.
但这里的复杂性是grepped来自另一个文件的变量(行)。 I cannot figure out how to do this using functions like re.findall()
我无法弄清楚如何使用re.findall()等函数来做到这一点
file1: 文件1:
1 20 200
1 30 300
file2: 文件2:
1 20 200 0.1 0.5
1 20 200 0.3 0.1
1 30 300 0.2 0.6
1 40 400 0.9 0.6
2 50 300 0.5 0.7
Each line from file1 is my pattern; file1中的每一行都是我的模式; and I need to search such pattern from file2.
我需要从file2中搜索这样的模式。 Then result should be:
那么结果应该是:
1 20 200 0.1 0.5
1 20 200 0.3 0.1
1 30 300 0.2 0.6
I've been trying to solve the problem using either bash or python,but cannot figure out. 我一直在尝试使用bash或python解决问题,但无法搞清楚。 thx
谢谢
Here's a non-regex based solution: 这是一个非正则表达式的解决方案:
with open('/tmp/file1') as f:
lines1 = f.readlines()
with open('/tmp/file2') as f:
for line in f:
if any(line.startswith(x.strip()) for x in lines1):
print line,
You can take advantage of the fact the the |
你可以利用
|
的事实 character in a regular expression means to match either the pattern on its left, or the pattern on its right: 正则表达式中的字符表示匹配左侧的模式或右侧的模式:
import re
with open('file1') as file1:
patterns = "|".join(re.escape(line.rstrip()) for line in file1)
regexp = re.compile(patterns)
with open('file2') as file2:
for line in file2:
if regexp.search(line):
print line.rstrip()
When I tried this on your sample files, it output: 当我在您的示例文件上尝试此操作时,它输出:
1 20 200 0.1 0.5
1 20 200 0.3 0.1
1 30 300 0.2 0.6
Incidentally, if you want to solve this problem in bash, the following should do it: 顺便说一下,如果你想在bash中解决这个问题,下面应该这样做:
grep -f file1 file2
I think you'll need your own loop 我想你需要自己的循环
file1patterns = [ re.Pattern(l) for l in f1.readlines() ]
lineToMatch = 0
matchedLines = []
for line in f2.readlines():
if file1patterns[lineToMatch].matches(line):
matchedLines += line
lineToMatch += 1
else:
lineToMatch = 0
matchedLines = []
if len(matchedLines) == len(file1patterns)
print matchedLines
lineToMatch = 0
matchedLines = []
(Not actual compiling Python, but hopefully enough for you to move forward) (不是实际编译Python,但希望你能继续前进)
Step 1: Read in all lines from file 1, split them and add them as tuples to a set. 步骤1:读入文件1中的所有行,拆分它们并将它们作为元组添加到集合中。 This will help us to do faster lookups in the next step.
这将有助于我们在下一步中更快地进行查找。
with open('file1', 'r') as f:
file1_lines = set([tuple(line.strip().split()) for line in f])
Step 2: Filter lines from file2 that meet your criteria ie if they start with any of the lines in file1: 第2步:从file2过滤符合条件的行,即如果它们以file1中的任何行开头:
with open('file2', 'r') as f2:
for line in itertools.ifilter(lambda x: tuple(x.split()[:3]) in file1_lines, f2):
print line
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