Regex : Split on comma , but exclude commas within parentheses and quotes(Both single & Double)

Question

I have one string

5,(5,5),C'A,B','A,B',',B','A,',"A,B",C"A,B" 

I want to split it on comma but need to exclude commas within parentheses and quotes(Both single and double quotes).

Like this

5 (5,5) C'A,B' 'A,B' ',B' 'A,' "A,B" C"A,B"

Using java Regular Expression how to achieve this ??

Answer 1

You can use this regex:

String input = "5,(5,5),C'A,B','A,B',',B','A,',\"A,B\",C\"A,B\"";
String[] toks = input.split( 
                ",(?=(([^']*'){2})*[^']*$)(?=(([^\"]*\"){2})*[^\"]*$)(?![^()]*\\))" );
for (String tok: toks)
    System.out.printf("<%s>%n", tok);

Output:

<5>
<(5,5)>
<C'A,B'>
<'A,B'>
<',B'>
<'A,'>
<"A,B">
<C"A,B">

Explanation:

,                         # Match literal comma
(?=(([^']*'){2})*[^']*$)  # Lookahead to ensure comma is followed by even number of '
(?=(([^"]*"){2})*[^"]*$)  # Lookahead to ensure comma is followed by even number of "
(?![^()]*\\))             # Negative lookahead to ensure ) is not followed by matching
                          # all non [()] characters in between