Re^2: How do I delete from a delimiter to the end of a file?

.*? usually comes with a speed penalty (unless the optimizer eliminates running .*? at all), as Perl needs to do bookkeeping for possible backtracking.

I'd write it as:

   s/------ Yahoo[^\cb]*+//g;    # Keeps the ^B
   s/------ Yahoo[^\cb]*+\cB//;  # Removes the ^B as well.
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Re^3: How do I delete from a delimiter to the end of a file? by ikegami (Patriarch) on Aug 25, 2008 at 20:34 UTC
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Re^4: How do I delete from a delimiter to the end of a file? by JavaFan (Canon) on Aug 26, 2008 at 06:41 UTC
That surprises me, and I wonder why .? is somewhat faster than a more explicite pattern. However, I'd still shy away from using .?. Consider the effect of a slight change of the string we are matching against (basically, replacing the \cB with \cA): use Benchmark qw( cmpthese ); my $ad = <<'__EOI__'; ------ Yahoo meow meow meow meow meow meow meow meow woof woof woof woof jabberwocky foo bar! foo!! __EOI__ my $email = join '', map chr(rand(26)+ord('a')), 1..2000; our $file = "$email\n$ad\cA" x 1000; cmpthese(-3, { ikegami => 'use strict; use warnings; my $x = our $file; $x +=~ s/----- - Yahoo.?(?=\cB)//sg;', JavaFan => 'use strict; use warnings; my $x = our $file; $x +=~ s/----- - Yahoo[^\cB]+//g;', JavaFan_noplus => 'use strict; use warnings; my $x = our $file; $x +=~ s/----- - Yahoo[^\cB]*//g;', }); __END__ (warning: too few iterations for a reliable count) Rate ikegami JavaFan JavaFan_noplus ikegami 0.264/s -- -98% -98% JavaFan 16.2/s 6053% -- -1% JavaFan_noplus 16.5/s 6135% 1% -- [download]	[reply] [d/l]