On Fri, May 28, 2010 at 14:46, Uri Guttman <u...@stemsystems.com> wrote: >>>>>> "CO" == Chas Owens <chas.ow...@gmail.com> writes: > > CO> On Fri, May 28, 2010 at 12:44, Uri Guttman <u...@stemsystems.com> wrote: > > >> the negated char class is usually faster than most similar methods. i > >> just like it as it says what i really want - a string without any - chars. > >> also anchoring helps too in saying this string must be at the beginning > >> (he wants the first field). > > CO> Really? I have never found it so. Could you explain what is wrong > CO> with my benchmark (I get similar results on 5.12)? > > on the surface i see nothing wrong with your benchmark. the speed > differences are relatively minor in all three cases. i distinctly recall > that negated char classes were faster but it could be for older > perls. they have continually optimized the regex engine over the years. snip
Yeah, I vaguely remember people commenting about that back in the 5.6 time frame, but I thought it was bunk then as well. Any speed difference tends to be very small (< 10%) in these sorts of cases. It is like arguing about which is better my $x = 'foo'; or my $x = "foo"; For me, it comes down to size and readability. I find my $x = $s =~ /(.*?)-/ ? $1 : ""; easier for my brain to parse than my $x = $s =~ /^([^-]+)-/ ? $1 : ""; The dual meanings of ^, the possible meanings of - in a character class, and the repetition of - makes it hard for me to see what it is looking for. Of course, my code base is littered with the .*? construct, so that biases me as well. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
