Python and regex to remove parenthesis in a file

Question

xml file with about 2000 (texthere) parenthesis. I need to remove the parenthesis and text within it. I tried but am getting an error :(

import re, sys

    fileName = (sys.argv[2])


    with open(fileName) as f:

        input = f.read()
        output = re.sub(r'\(\w*\)', '', input)
        print fileName + " cleaned of all parenthesis"

and my error :

Traceback (most recent call last):
  File "/Users/eeamesX/work/data-scripts/removeParenFromXml.py", line 4, in <module>
    fileName = (sys.argv[2])
IndexError: list index out of range

I changed the (sys.argv[1])...I get no errors but also the parenthesis in my file.xml do not get removed?

How are you calling the script? Have you tried `print sys.argv` to see what it holds? — hjpotter92, Sep 24 '15 at 15:48
What command line parameters did you pass? Python indexing is 0-based... — jonrsharpe, Sep 24 '15 at 15:48
I threw your `\(\w*\)` (and even @hjpotter92 's suggestion of `\(\w*?\)` into https://regex101.com/r/kB2lU1/3 and looking under `code generator` on the left, the regex is nearly the same as yours (with an additional `u` param next to the text string). — OnlineCop, Sep 24 '15 at 15:59

score 1 · Accepted Answer · answered Sep 24 '15 at 15:58

1

Since you're calling the script as follows:

python removeparenthesis.py filename.xml

the XML file name will appear under sys.argv[1].

Also, you'd need to use lazy matching in your pattern:

r'\(\w*?\)'    # notice the ?

A better pattern would be:

r'\([^)]*\)'

answered Sep 24 '15 at 15:58

hjpotter92

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I just tried this, and it seems to go into my file, but no parenthesis are removed. File stays the same ? – Anekdotin Sep 24 '15 at 16:06
@Eddwinn You're printing `filename`; and not the substituted string (`output`). – hjpotter92 Sep 24 '15 at 16:08

OnlineCop · Answer 2 · 2015-09-24T15:55:54.547

0

Do you have nested parens?

stuff (words (inside (other) words) eww)

Will you have multiple groups of parens?

stuff (first group) stuff (second group)

Does text within parens have spaces?

stuff (single_word)
stuff (multiple words)

A simple regex could be \(.*?\) although you'll see that the nested parens are not caught (which is fine if you do NOT expect nested parens):

https://regex101.com/r/kB2lU1/1

Edit:

https://regex101.com/r/kB2lU1/2 may be able to handle some of those nested parens, but may still break depending on different types of edge cases.

You'll need to specify what kinds of edge cases you expect so the answer can be better tailored to your needs.

edited Sep 24 '15 at 15:55

answered Sep 24 '15 at 15:52

OnlineCop

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It is an easier one.. just (datafalse) or (variant) No nested, or spaces – Anekdotin Sep 24 '15 at 15:55
Your example with `\w*` suggests that you can have empty `()` parens, and you want to remove those as well. Is that correct? – OnlineCop Sep 24 '15 at 15:56
I have no empty parenthesis..there are a thousand parenthesis containing those 2 – Anekdotin Sep 24 '15 at 15:59

Python and regex to remove parenthesis in a file

2 Answers2