I would like to retrieve everything before a specific string in a text file using regex in Python. For example with the line
text = 'What I want is a red car'
I would like to retrieve everything that is before "a red car", that is:
result = 'What I want is'
The whole string "a red car" is important, not only "red" or "car" separately!
Thanks in advance!
If you need to use a regex for this :
regex = re.compile('(?P<before_red_car>.+) a red car')
regex.search("What i want is a red car").group('before_red_car')
If you don't want to name your group :
regex = re.compile('(.+)a red car')
regex.search("What i want is a red car").group(1)
If you need to catch everything including newlines, add the re.DOTALL flag.
However, doing
text = 'What I want is a red car'
text.split('a red car')[0]
Or even :
text = 'What I want is a red car'
text.replace('a red car', '')
Work too, and are arguably easier to understand. They are also twice faster :
timeit.timeit(lambda: text.split('a red car')[0])
0.5350678942020507
timeit.timeit(lambda: text.replace('a red car', ''))
0.5115460171814448
timeit.timeit(lambda: regex.search("What i want is a red car").group(1))
1.123993800741033
# Without re.compile()
timeit.timeit(lambda: re.search('(.+)a red car', text).group(1))
1.94518623436079
You can try this:
strIn = 'What I want is a red car'
searchStr = 'a red car'
print(strIn[:strIn.find(searchStr)])
This might help
text = 'What I want is a red car'
print(text[0:13])
What you want is a red car?
What you want... My point being, that this solution is not dynamic or flexible. Also, I just tested the above and it returns What I want i, which doesn't seem like what the OP wants
The whole string "a red car" is important,....butI would like to retrieve everything that is before "a red car"