comment on

I don't know where I got the idea in my brain that the global substitute expression was faster. It could very well be that I figured that in some normal case, the difference didn't matter based upon some other benchmark.

I re-wrote your benchmark and yes, this does show that using 2 lines of Perl to do this is faster!
I show my code below..

use strict;
use warnings;
use Benchmark qw(cmpthese);
use Data::Dumper;
use List::Util qw(pairmap);

my @strings = (
  no_trim_short         => 'asd',
  no_trim_mid           => 'asdasdasdasdasdasdasd',
  no_trim_long          => 'asd' x 50,
  no_trim_mid_with_ws   => 'asd asd asd asd asd asd asd',
  no_trim_long_with_ws  => (join ' ', ('asd') x 20),

  short         => '    asd    ',
  mid           => '    asdasdasdasdasdasdasd    ',
  long          => '    '.('asd' x 20).'    ',
  mid_with_ws   => '    asd asd asd asd asd asd asd    ',
  long_with_ws  => '    '.(join ' ', ('asd') x 20).'    ',
);


my @test_line_array = pairmap{$b}@strings;
#print "$_\n" for @test_line_array;  #for debug


cmpthese (100000, {
  global => sub{
     my @copy = @test_line_array;
     $_ =~ s/\A\s+|\s+\z//g foreach @copy;
     },
  global2 => sub{
     my @copy = @test_line_array;
     $_ =~ s/^\s+|\s+$//g foreach @copy;
     },   
  twoLines => sub {
      my @copy = @test_line_array;
      s/\A\s+//, s/\s+\z// foreach @copy;
    },
  twoLines2 => sub {
      my @copy = @test_line_array;
      s/^\s+//, s/\s+$// foreach @copy;
    },  
  dollar1 => sub {
      my @copy = @test_line_array;
      s/\A\s*(.*?)\s*\z/$1/ foreach @copy;
    }
});

print "\n";

__END__
              Rate    global   global2   dollar1  twoLines twoLines2
global     33681/s        --        0%      -21%      -68%      -68%
global2    33681/s        0%        --      -21%      -68%      -68%
dollar1    42662/s       27%       27%        --      -60%      -60%
twoLines  106610/s      217%      217%      150%        --       -0%
twoLines2 106724/s      217%      217%      150%        0%        --
[download]

In reply to Re^4: How to trim a line from leading and trailing blanks without using regex or non-standard modules by Marshall
in thread How to trim a line from leading and trailing blanks without using regex or non-standard modules by likbez

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