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Re: Re: Re^2: sorting entires by date

by BrowserUk (Pope)
on Jan 02, 2004 at 01:34 UTC ( #318214=note: print w/replies, xml ) Need Help??

in reply to Re: Re^2: sorting entires by date
in thread sorting entires by date

In a simplistic benchmark of a thousand records the straight substr $a cmp substr $b comes out over 180% quicker than the ST version. Using a GRT saves another 14%.

The cost of the split in the ST outweights the repeated substr in this case.

#! perl -slw use strict; use Benchmark qw[ cmpthese ]; open IN, '<', 'test.dat' or die $!; our @lines = <IN>; close IN; print "Sorting ", scalar @lines, $/; cmpthese( -3, { ST => q[ my @sorted = map $_->[0], sort{ $a->[4] <=> $b->[4] } map [ $_, split /:/ ], @lines; ], XX => q[ my @sorted = sort{ substr( $a, 19 ) cmp substr( $b, 19 ) } @lines; ], GRT=> q[ my @sorted = map{ substr $_, 10 } sort map{ substr( $_, 20 ) . $_ } @lines; ], }); __END__ P:\test>318176 Sorting 1000 Rate ST XX GRT ST 6.70/s -- -65% -69% XX 19.1/s 186% -- -13% GRT 21.9/s 227% 14% --

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail

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