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Re^5: Need Speed:Search Tab-delimited File for pairs of names

by Laurent_R (Parson)
on Dec 17, 2013 at 10:02 UTC ( #1067443=note: print w/ replies, xml ) Need Help??


in reply to Re^4: Need Speed:Search Tab-delimited File for pairs of names
in thread Need Speed:Search Tab-delimited File for pairs of names

Yes, indeed, a RE search without meta-characters is fast. But index is still faster:

$ perl index_regex_bench.pl Rate Regex Index Regex 5010020/s -- -23% Index 6544503/s 31% --
This is one of the code versions I used, the one with which I obtained the above timings:
#!/usr/bin/perl use Benchmark qw(:all); use strict; use warnings; my $sentence = "The quick brown for jumps over the lazy dog"; my $results = timethese(5000000, { 'Index' => \&code1, 'Regex' => \&code2, }, 'none' ); cmpthese( $results ) ; #------ sub code1 { my $val = index $sentence, "fox" ; } #------ sub code2 { my $val = ($sentence =~ /fox/); }
Using a precompiled regex does not improve the speed of RE search in this case, quite the contrary.


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