python 匹配文件对象中的多行正则表达式
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Match multiline regex in file object
提问by user265978
How can I extract the groups from this regex from a file object (data.txt)?
如何从文件对象 (data.txt) 中提取此正则表达式中的组？
import numpy as np
import re
import os
ifile = open("data.txt",'r')
# Regex pattern
pattern = re.compile(r"""
^Time:(\d{2}:\d{2}:\d{2}) # Time: 12:34:56 at beginning of line
\r{2} # Two carriage return
\D+ # 1 or more non-digits
storeU=(\d+\.\d+)
\s
uIx=(\d+)
\s
storeI=(-?\d+.\d+)
\s
iIx=(\d+)
\s
avgCI=(-?\d+.\d+)
""", re.VERBOSE | re.MULTILINE)
time = [];
for line in ifile:
match = re.search(pattern, line)
if match:
time.append(match.group(1))
The problem in the last part of the code, is that I iterate line by line, which obviously doesn't work with multiline regex. I have tried to use pattern.finditer(ifile)like this:
代码最后一部分的问题是我逐行迭代，这显然不适用于多行正则表达式。我试过这样使用pattern.finditer(ifile)：
for match in pattern.finditer(ifile):
print match
... just to see if it works, but the finditer method requires a string or buffer.
...只是为了看看它是否有效，但 finditer 方法需要一个字符串或缓冲区。
I have also tried this method, but can't get it to work
我也试过这个方法，但不能让它工作
matches = [m.groups() for m in pattern.finditer(ifile)]
Any idea?
任何的想法？
After comment from Mike and Tuomas, I was told to use .read().. Something like this:
在 Mike 和 Tuomas 发表评论后，有人告诉我使用 .read().. 像这样：
ifile = open("data.txt",'r').read()
This works fine, but would this be the correct way to search through the file? Can't get it to work...
这工作正常，但这是否是搜索文件的正确方法？无法让它工作...
for i in pattern.finditer(ifile):
match = re.search(pattern, i)
if match:
time.append(match.group(1))
Solution
解决方案
# Open file as file object and read to string
ifile = open("data.txt",'r')
# Read file object to string
text = ifile.read()
# Close file object
ifile.close()
# Regex pattern
pattern_meas = re.compile(r"""
^Time:(\d{2}:\d{2}:\d{2}) # Time: 12:34:56 at beginning of line
\n{2} # Two newlines
\D+ # 1 or more non-digits
storeU=(\d+\.\d+) # Decimal-number
\s
uIx=(\d+) # Fetch uIx-variable
\s
storeI=(-?\d+.\d+) # Fetch storeI-variable
\s
iIx=(\d+) # Fetch iIx-variable
\s
avgCI=(-?\d+.\d+) # Fetch avgCI-variable
""", re.VERBOSE | re.MULTILINE)
file_times = open("output_times.txt","w")
for match in pattern_meas.finditer(text):
output = "%s,\t%s,\t\t%s,\t%s,\t\t%s,\t%s\n" % (match.group(1), match.group(2), match.group(3), match.group(4), match.group(5), match.group(6))
file_times.write(output)
file_times.close()
Maybe it can be written more compact and pythonic though....
也许它可以写得更紧凑和 Pythonic....
采纳答案by Mike
You can read the data from the file object into a string with ifile.read()
您可以使用以下命令将文件对象中的数据读入字符串 ifile.read()
回答by Tuomas Pelkonen
Why don't you read the whole file into a buffer using
为什么不使用将整个文件读入缓冲区
buffer = open("data.txt").read()
and then do a search with that?
然后用那个搜索？
回答by SilentGhost
times = [match.group(1) for match in pattern.finditer(ifile.read())]
finditeryield MatchObjects. If the regex doesn't match anything timeswill be an empty list.
finditer产量MatchObjects。如果正则表达式不匹配任何内容times将是一个空列表。
You can also modify your regex to use non-capturing groups for storeU, storeI, iIxand avgCI, then pattern.findallwill contain only matched times.
您还可以修改您正则表达式使用非捕获组storeU，storeI，iIx和avgCI，然后pattern.findall将只包含匹配次数。
Note: naming variable timemight shadow standard library module. timeswould be a better option.
注意：命名变量time可能会影响标准库模块。times将是一个更好的选择。
