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Re^3: difference in regex

by haukex (Chancellor)
on May 29, 2018 at 14:30 UTC ( #1215380=note: print w/replies, xml ) Need Help??


in reply to Re^2: difference in regex
in thread difference in regex

Although personally I'd still use a conditional, of course it's possible to do it all in one regex. One way is by making the comma optional by putting a ? on a group, in this case I'm using a non-capturing (?:...) group, and I had to make the first part of the regex non-greedy so that it doesn't swallow an existing comma:

use warnings; use strict; use Test::More; my $regex = qr/ ^ (.*?) (?: , ([^,]*) )? $ /x; ok "abc"=~$regex; is $1, "abc"; is $2, undef; ok "abc,5"=~$regex; is $1, "abc"; is $2, 5; ok "a,b,c,5"=~$regex; is $1, "a,b,c"; is $2, 5; done_testing;

Update: An alternative that says a little more explicitly: either match a string with no commas in it, or, if there are commas, I want to match the thing after the last one: /^ (?| ([^,]*) | (.*) , ([^,]*) ) $/x Update 2: And it turns out this regex is much faster than the above! (try using it in this benchmark)

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