Yes here is the benchmark that I ran. Fixed string grep is crazy fast. This is run on a 500MB file.

#!/usr/bin/perl

use strict;
use Benchmark qw(cmpthese);

my $fileName = "data2";
my $string = "test";

print "case1 finds ", &case1, " matches \n";
print "case2 finds ", &case2, " matches \n";

cmpthese (10, {
    case0 => sub {&case0},
    case1 => sub {&case1},
    case2 => sub {&case2},
    },
);

sub case0 {
    open(my $file, '<', "$fileName") or die $!;

    while (<$file>) {
    }
}

sub case1 {
    open(my $file, '<', "$fileName") or die $!;
    my $matchCount = 0;

    while (<$file>) {
        $matchCount++ if ($_ =~ /$string/o);
    }

    return $matchCount;
}

sub case2 {
    my $matchCount = `grep -c -F "$string" $fileName`;
    chomp $matchCount;

    return $matchCount;
}



case1 finds 354 matches
case2 finds 354 matches

          s/iter     case1 emptyLoop     case2
case1      8.08        --       -36%      -92%
case0      5.16       57%        --       -88%
case2      0.632     1178%      716%      --

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In reply to Re^2: search array for closest lower and higher number from another array by bigbot
in thread search array for closest lower and higher number from another array by bigbot

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