Remove All Commas Between Quotes

Question

I’m trying to remove all commas that are inside quotes (") with python:

'please,remove all the commas between quotes,"like in here, here, here!"'
                                                          ^     ^

I tried this, but it only removes the first comma inside the quotes:

re.sub(r'(".*?),(.*?")',r'12','please,remove all the commas between quotes,"like in here, here, here!"')

Output:

'please,remove all the commas between quotes,"like in here here, here!"'

How can I make it remove all the commas inside the quotes?

Asked By: carloabelli

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Source

Answer 1

Assuming you don’t have unbalanced or escaped quotes, you can use this regex based on negative lookahead:

>>> str = r'foo,bar,"foobar, barfoo, foobarfoobar"'
>>> re.sub(r'(?!(([^"]*"){2})*[^"]*$),', '', str)
'foo,bar,"foobar barfoo foobarfoobar"'

This regex will find commas if those are inside the double quotes by using a negative lookahead to assert there are NOT even number of quotes after the comma.

Note about the lookaead (?!...):

([^"]*"){2} finds a pair of quotes
(([^"]*"){2})* finds 0 or more pair of quotes
[^"]*$ makes sure we don’t have any more quotes after last matched quote
So (?!...) asserts that we don’t have even number of quotes ahead thus matching commas inside the quoted string only.

Answered By: anubhava

Answer 2

You can pass a function as the repl argument instead of a replacement string. Just get the entire quoted string and do a simple string replace on the commas.

>>> s = 'foo,bar,"foobar, barfoo, foobarfoobar"'
>>> re.sub(r'"[^"]*"', lambda m: m.group(0).replace(',', ''), s)
'foo,bar,"foobar barfoo foobarfoobar"'

Answered By: Brendan Abel

Answer 3

What about doing it with out regex?

input_str = '...'

first_slice = input_str.split('"')

second_slice = [first_slice[0]]
for slc in first_slice[1:]:
    second_slice.extend(slc.split(','))

result = ''.join(second_slice)

Answered By: Dan

Answer 4

Here is another option I came up with if you don’t want to use regex.

input_str = 'please,remove all the commas between quotes,"like in here, here, here!"'

quotes = False

def noCommas(string):
    quotes = False
    output = ''
    for char in string:
        if char == '"':
            quotes = True
        if quotes == False:
            output += char
        if char != ',' and quotes == True:
            output += char
    return output

print noCommas(input_str)

Answered By: albydarned

Answer 5

The above answer with for-looping through the string is very slow, if you want to apply your algorithm to a 5 MB csv file.

This seems to be reasonably fast and provides the same result as the for loop:

#!/bin/python3

data = 'hoko foko; moko soko; "aaa mo; bia"; "ee mo"; "eka koka"; "koni; masa"; "co co"; ehe mo; "bi; ko"; ko man "ka ku"; "ki; ko"n "ko;ma"; "ki ma"n"ehe;";koko'

first_split=data.split('"')
split01=[]
split02=[]
for slc in first_split[0::2]:
    split01.append(slc)
for slc in first_split[1::2]:
    slc_new=",".join(slc.split(";"))
    split02.append(slc_new)

resultlist = [item for sublist in zip(split01, split02) for item in sublist]
if len(split01) > len (split02):
   resultlist.append(split01[-1])
if len(split01) < len (split02):
   resultlist.append(split02[-1])
   
result='"'.join(resultlist)
print(data)
print(split01)
print(split02)
print(result)

Results in:

hoko foko; moko soko; "aaa mo; bia"; "ee mo"; "eka koka"; "koni; masa"; "co co"; ehe mo; "bi; ko"; ko ma
 "ka ku"; "ki; ko"
 "ko;ma"; "ki ma"
"ehe;";koko
['hoko foko; moko soko; ', '; ', '; ', '; ', '; ', '; ehe mo; ', '; ko man ', '; ', 'n ', '; ', 'n', ';koko']
['aaa mo, bia', 'ee mo', 'eka koka', 'koni, masa', 'co co', 'bi, ko', 'ka ku', 'ki, ko', 'ko,ma', 'ki ma', 'ehe,']
hoko foko; moko soko; "aaa mo, bia"; "ee mo"; "eka koka"; "koni, masa"; "co co"; ehe mo; "bi, ko"; ko ma
 "ka ku"; "ki, ko"
 "ko,ma"; "ki ma"
"ehe,";koko

Answered By: amirzolal

Remove All Commas Between Quotes

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