Regex question

AlanOlsen has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to split on a comma, but only where it is not in parenthisis.

For example:

var-a numeric (10,0) = NULL, var-b char (10) = NULL
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would split to:

var-a numeric (10,0) = NULL
 var-b char (10) = NULL
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instead of:

var-a numeric (10
0) = NULL
 var-b char (10) = NULL
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Ideas? I should know this, but i have not had enough coffee today.

Comment on Regex question Select or Download Code

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Re: Regex question by TedYoung (Deacon) on Oct 20, 2005 at 17:48 UTC
Well, if you don't have to worry about nested parens, this seems to work for me: `/,(?![^()]*\))/` [download] Ted Young `($$<<$$=>$$<=>$$<=$$>>$$) always returns 1. :-)`	[reply] [d/l] [select]
Re^2: Regex question by AlanOlsen (Initiate) on Oct 20, 2005 at 18:10 UTC
Works great! Thanks!	[reply]
Re: Regex question by ww (Archbishop) on Oct 20, 2005 at 18:01 UTC
Here's one ugly way: UPDATE: UGLIER than I realized; see Roy Johnson's below `use strict; use warnings; use vars qw ($foo $bar @bar); $foo = 'var-a numeric (10,0) = NULL, var-b char (10) = NULL'; @bar = split /([^(,)].*,)+/, $foo; # [^(,)]... happens to work here, but is NOT a generally appli +cable approach! foreach $bar(@bar) { print "$bar\n"; }` [download] OUTPUT: var-a numeric (10,0) = NULL, var-b char (10) = NULL	[reply] [d/l]
Re^2: Regex question by Roy Johnson (Monsignor) on Oct 20, 2005 at 18:06 UTC
Not only ugly, it doesn't match the OP's spec. It matches everything from the first non-special character through the last comma. Try it with `$foo = 'var-a numeric (10,0) = NULL, var-b char (10) = NULL, var-c dum +my (1, 5)';` [download] Since you're specifying a capture group, you're probably better trying for a `m//g` style capture, rather than using `split`. Like so: `my $str = 'var-a numeric (10,0) = NULL, var-b char (10) = NULL, var-c +dummy (1, 5)'; my @bits = $str =~ /(?:^\|,) # Match starting at beginning of string or a comma ( # Capture (?: # group of [^(,] # non-parens \| # or $.?$ # open-paren to close-paren ) # as many times as possible )/gx; print ">$_<\n" for @bits;` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l] [select]
Re: Regex question by Nkuvu (Priest) on Oct 20, 2005 at 17:56 UTC
I'd suggest a module like Text::xSV, but I am not sure if it will work with parens. I do know that it works well with quoted comma-separated values, though.	[reply]