Thanks for writing. Your code works for this example but doesn't get exactly what I need. It's important to me to keep $1 and $2 separate because Yeas and Nays are paired together (these are votes on bills). But sometimes, you only have Yeas (eg, a unanimous vote).
That is why I want to see: 123 <- from the first yea ($1) (nothing) <- no nay! ($2) 456 <- from the second yea ($1) 789 <- from the second nay ($2) Hence why I put a ? After the (?:Nay (.*?)x) regexp; the idea being this can appear zero or one times. But if I do this, I get no matches on the 'nays' or $2. -----Original Message----- From: Randy W. Sims [mailto:[EMAIL PROTECTED] Sent: Sunday, April 04, 2004 9:30 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: Regular expression question: non-greedy matches Boris Shor wrote: > Hello, > > Perl beginner here. I am having difficulty with a regular expression > that uses non-greedy matches. Here is a sample code snippet: > > $test = "Yea 123xrandomYea 456xdumdumNay 789xpop"; > while ($test =~ /Yea (.*?)x.*?(?:Nay (.*?)x)?/g) > { > print "$1\n"; > print "$2\n"; > } > > The idea is that every 'phrase' is delimited with an 'x' and there are > random letters between phrases. > > I expect to see: > > 123 > > 456 > 789 > > But instead I get: > > 123 > > 456 > > Why don't I get the second part of the regular expression? Well, the first thing that I notice is that you never capture anything in $2. We could get it to match the second time through, but it is never gonna match in the first iteration. That may be a clue that there is a better way. Looking at the two parts of the regex, I see that they are basically the same except for 'Yea' vs 'Nay'. This indicates that alternation be usefull. Combining them, I get: while ($test =~ /(?:Yea|Nay) (\d+)x/g) { print "$1\n"; } Does this help? Randy. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response> -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
