CODEWITHSUNDEEP
pythonregex
ZVT
ZVT

Reputation: 33

Replace spaces with underscores but not all of them

I'm pretty new to Python, but we are working on cleaning up some text files, and, among others, I will need to do the following: Replace spaces with underscores, but only in some cases. The cases are such that the beginning is marked with /2, and the end is marked with /1.

E.g.:

Here is some text, /2This is an example/1 only.

I would like to turn this into:

Here is some text, This_is_an_example only.

I know how to do a universal replace (either just with python or with regex), and also know how to do a regex search that would match all the /2...../1 expressions. But cannot figure out how to combine those: to replace ONLY when the expression is found, and leave the rest of the text alone. I would be very grateful for any suggestions!

People keep asking for a code I have and/or point me to basic python documentations. It is a relatively long program since we have to do a lot of things with our input, and this is just one of them. It would be part of a series of find and replace steps; here are some others:

for x in handle:
    for r in (("^009", ""),("/c", ""),("#", ""),("\@", "")):
        x = x.replace(*r)
        # get rid of all remaining latex commands
    x = re.sub("\\\\[a-z]+", "", x)
    x = re.sub("\.h/.*?//", "", x)
    # get rid of punctuation
    x = re.sub('\.', '', x)
    x = re.sub('\,', '', x)
    x = re.sub('\;', '', x)
    x = re.sub('\n', ' \n', x)
    x = re.sub('\|.*?\|', '', x)
    x = re.sub('\'', '', x)
    x = re.sub('\"', '', x)
    # Here's an initial attempt
    y = re.findall('\/2.*?\/1', x)
    for item in y:
        title = re.sub('\s', '_', item)
#but the question is how do I place these things back into x?
    s.write(x)
s.close()
handle.close()

Edit 2: Here is a(nother) thing that does NOT work:

for item in re.findall('\/2.*?\/1', x):
        item = re.sub('\s', '_', item)

Upvotes: 2

Views: 299

Answers (1)

Ryszard Czech
Ryszard Czech

Reputation: 18641

Use re.sub with a lambda:

x = re.sub(r'/2.*?/1', lambda x: re.sub(r'\s+', '_', x.group()), x)

Match all strings between /2 and /1 and replace whitespace strings only there with the nested re.sub.

Upvotes: 3

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