Hi guys, I have this code working almost perfectly. I am reading the file "A" and looking for a match in file "B" and decrement a value from file A. My big problem is that I am doing a full scan in the file "B" and my file "A" has 75k lines and file "B" has 880 lines. Do you have any idea about how to avoid full scan? Example of two files File "A"

l100101,aaaaaaa,a_0100,loc,10,1

l100101,aaaaaaa,a_0100,loc,11,1

l100101,aaaaaaa,a_0100,loc,12,6

File "B"

l103709,bbbbbbb,c_0200,929

l100109,bbbbbbb,b_0100,442

l100107,bbbbbbb,c_0300,389

#!/usr/bin/perl

use strict;
use warnings;

$|=1;

my $filea = $ARGV[0];
my $fileb = $ARGV[1];
my $FileC = "result.csv";


open ( FA, '<', $filea) || die ( "File $filea Not Found!" );
open ( FB, '<', $fileb) || die ( "File $fileb Not Found!" );
open ( FC, ">", $FileC) || die ( "File $FileC Not Found!" );

my @B;
while ( <FB> ) {
    chomp;
    my($look, $sec, $cls, $max) = split ",";
    push @B, [$look, $sec, $cls, $max];
}

my @A;
while ( <FA> ) {
    chomp;
    my($look, $sec, $cls, $att, $idx, $qtd) = split ",";
    push @A, [$look, $sec, $cls, $att, $idx, $qtd];
}

my $i = 1;
my $j = 0;
my $k = 0;
my $count=0;
while ( 1 ) {
    # -- keep looping til nothing is modified --
    my $modified=0;
    $j = 0;
    foreach my $row ( @A ) {
        # -- loop through FileA, $j is rowcount --
        $j++;
        $k=0;
        # -- loop through FileB, $k is linecount --
        foreach my $line ( @B ) {
            $k++;
            my $idx1= @$line[0].@$line[1].@$line[2];
            my $idx2= @$row[0].@$row[1].@$row[2];
            # -- has to match on the index fields --
            if ($idx1 eq $idx2) {
                my $max = @$line[3];
                my $tot = @$row[5] -1;
                last if $count == $max;
                if ( $tot >= 0 ) {
                        #print "FileA[".$j."]: ".join(",", @$row[0],@$
+row[1],@$row[3],@$row[4],@$row[5]  )."\n";
                        print FC join(",", @$row[0],@$row[1],@$row[3],
+@$row[4],$max  )."\n";
                        $count++;

                    @$row[5]=$tot;
                    $modified = 1;
                }
             }
        }
    }
    if ((! $modified ) || ($i > 10)) {
        last;
    }
}

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In reply to how to avoid full scan in file. by EBK

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