Regex find comma not inside quotes

Question

I\'m checking line by line in C#

Example data:

bob jones,123,55.6,,,\"Hello , World\",,0
jim neighbor,432,66.5,,,Andy \"Blank,,1
john smith,555,77.4,         


        

Answer 1

The below regex is for parsing each fields in a line, not an entire line

Apply the methodical and desperate regex technique: Divide and conquer

Case: field does not contain a quote

• abc,
• abc(end of line)

[^,"]*(,|$)

Case: field contains exactly two quotes

• abc"abc,"abc,
• abc"abc,"abc(end of line)

[^,"]*"[^"]*"[^,"]*(,|$)

Case: field contains exactly one quote

• abc"abc(end of line)
• abc"abc, (and that there's no quote before the end of this line)

[^,"]*"[^,"]$

[^,"]*"[^"],(?!.*")

Now that we have all the cases, we then '|' everything together and enjoy the resultant monstrosity.

Answer 2

Stand back and be amazed!

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Here is the regex you seek:

(?!\B"[^"]*),(?![^"]*"\B)

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Here is a demonstration:

regex101 demo

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• It does not match the second line because the " you inserted does not have a closing quotation mark.
• It will not match values like so: ,r"a string",10 because the letter on the edge of the " will create a word boundary, rather than a non-word boundary.

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Alternative version

(".*?,.*?"|.*?(?:,|$))

This will match the content and the commas and is compatible with values that are full of punctuation marks

regex101 demo

Answer 3

try this pattern ".*?"(*SKIP)(*FAIL)|, Demo

Answer 4

import re

print re.sub(',(?=[^"]*"[^"]*(?:"[^"]*"[^"]*)*$)',"",string)

Answer 5

The best answer written by Vasili Syrakis does not work with negative numbers inside quotation marks such as:

bob jones,123,"-55.6",,,"Hello , World",,0
jim neighbor,432,66.5

Following regex works for this purpose:

,(?!(?=[^"]*"[^"]*(?:"[^"]*"[^"]*)*$))

But I was not successful with this part of input:

,Andy "Blank,