Re^2: Matching simple patterns - is there a faster way?

Hi, please see my benchmark test


use strict;
use Benchmark qw(cmpthese);

# A big, sorted list (475254 elements)
my @list = ('a'..'zzzz');
##Put the list into a string

my $string = join(/ /, @list);

$string .= "\n";

cmpthese(0, {
       # Looking for a random item in @list with grep
        index => sub {
                # A random element in the list
                my $pattern = 'fqsu  fqsv  fqsw  fqsx  fqsy';
                my $result = index($string, $pattern);

        },
        # Looking for a random item in @list linearly (with foreach)
        regex  => sub {
                my $pattern = 'fqsu  fqsv  fqsw  fqsx  fqsy';
                $string =~ /$pattern/;
        },
    }

);
[download]

I also did another test where I read a proper HTML file and received similar results. Can you please tell me what you did different?

Everybody seems to think I'm lazy
I don't mind, I think they're crazy
Comment on Re^2: Matching simple patterns - is there a faster way?
Download Code

Replies are listed 'Best First'.
Re^3: Matching simple patterns - is there a faster way? by flexvault (Monsignor) on Aug 09, 2012 at 14:15 UTC
mrguy123, As requested ( I typed this in from the code ): `sub index { if ( index('yabba dabba doo','abba' ) >= 0 ) { } } sub regex { $_ = 'yabba dabba doo'; if ( /abba/ ) { } } cmpthese ( 500_000, { regex => sub { &regex }, index => sub { &index }, }, );` [download] I have found 'index' usually faster than 'regex' in this type of situation, but 'regex' has more power when needed. Regards...Ed "Well done is better than well said." - Benjamin Franklin	[reply] [d/l]

Replies are listed 'Best First'.

Re^3: Matching simple patterns - is there a faster way?
by flexvault (Monsignor) on Aug 09, 2012 at 14:15 UTC

mrguy123,

As requested ( I typed this in from the code ):

sub index
{  if ( index('yabba dabba doo','abba' ) >= 0 ) { }
}

sub regex
{   $_ = 'yabba dabba doo';
    if ( /abba/ ) { }
}

cmpthese ( 500_000, 
   {  regex => sub { &regex },
      index => sub { &index },
   },
 );
[download]

Regards...Ed

"Well done is better than well said." - Benjamin Franklin

[reply]
[d/l]