Python Regex: Find And Replace Commas Between Quotation Marks

I have a string, line = '12/08/2013,3,'9,25',42:51,'3,08','12,9','13,9',159,170,'3,19',437,' and I would like to find and replace the commas, between quotation marks, with ':'. Lo

Solution 1:

>>>import re>>>line = '12/08/2013,3,"9,25",42:51,"3,08","12,9","13,9",159,170,"3,19",437,'>>>re.sub(r'"(\d+),(\d+)"', r'\1:\2', line)
'12/08/2013,3,9:25,42:51,3:08,12:9,13:9,159,170,3:19,437,'

\1, \2 refer to matched groups.

---

Non-regex solution:

>>> ''.join(x if i % 2 == 0else x.replace(',', ':')
            for i, x inenumerate(line.split('"')))
'12/08/2013,3,9:25,42:51,3:08,12:9,13:9,159,170,3:19,437,'

Solution 2:

import re
line = '12/08/2013,3,"9,25",42:51,"3,08","12,9","13,9",159,170,"3,19",437,'
r = ""for t in re.split(r'("[^"]*")', line):
    if t[0] == '"': 
        t = t.replace(",", ":")[1:-1]
    r += t
print r

Prints:

12/08/2013,3,9:25,42:51,3:08,12:9,13:9,159,170,3:19,437,

Solution 3:

There is also a generic regex solution to replace any kind of fixed (and non-fixed, too) pattern in between double (or single) quotes: match the double- or single quoted substrings with the corresponding pattern, and use a callable as the replacement argumet to re.sub where you may manipulate the match:

1. Replacing commas in between double quotes with colons and remove the double quotes (the current OP scenario):

   re.sub(r'"([^"]*)"', lambda x: x.group(1).replace(',', ':'), line) (demo)# => 12/08/2013,3,9:25,42:51,3:08,12:9,13:9,159,170,3:19,437,

2. Replacing commas in between double quotes with colons and keep the double quotes:

   re.sub(r'"[^"]*"', lambda x: x.group(0).replace(',', ':'), line) (demo)# => 12/08/2013,3,"9:25",42:51,"3:08","12:9","13:9",159,170,"3:19",437,

3. Replacing commas in between double and single quotes with colons and keep the single/double quotes:

   re.sub(r''''[^']*'|"[^"]*"''', lambda x: x.group(0).replace(',', ':'), '''0,1,"2,3",'4,5',''') (demo)# => 0,1,"2:3",'4:5',

Also, if you need to handle escaped single and double quotes, consider using r"'[^\\']*(?:\\.[^\\']*)*'" (for single quoted substrings), r'"[^\\"]*(?:\\.[^\\"]*)*"' (for double quoted substrings) or for both - r''''[^\\']*(?:\\.[^\\']*)*'|"[^\\"]*(?:\\.[^\\"]*)*"''' instead of the patterns above.