python regular expression re.sub error

Question

I have a .csv files that might have brackets mixed in:

line = "fdf,dfdf,(1,2,3,4,5),(ss,dd),"

Now I want to replace all the () with "", so that it looks like this:

line = 'fdf,dfdf,"1,2,3,4,5","ss,dd",'

My code is:

line=re.sub(',(', ',"', line)
line=re.sub('),', '",', line)

However I got this error:

 ...
 File "/usr/local/Python-2.7/lib/python2.7/re.py", line 151, in sub
    return _compile(pattern, flags).sub(repl, string, count)
  File "/usr/local/Python-2.7/lib/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression
sre_constants.error: unbalanced parenthesis

What is wrong here?!!

Answer 1

how bout just simple string substitution

print strs.replace("(",'"').replace(")",'"')

no need for regex for this

Some people, when confronted with a problem, think “I know, I'll use regular expressions.” Now they have two problems.

Answer 2

( have special meaning in regular expressions you can escape them using \( or place them use square [] brackets.

>>> import re
>>> strs = "fdf,dfdf,(1,2,3,4,5),(ss,dd),"
>>> re.sub(r"[()]",'"',strs)
'fdf,dfdf,"1,2,3,4,5","ss,dd",'
#or
>>> re.sub(r"\(|\)",'"',strs)
'fdf,dfdf,"1,2,3,4,5","ss,dd",'

Answer 3

another one would be to consider this..

import re 
re.sub('\)', '\"', re.sub('\(', '\"', line))

what you do is replace one pran once and then replace the other one.