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changma_ha has asked for the wisdom of the Perl Monks concerning the following question:

Hi all i am trying to solve a problem for a long time. where i have data table in a text file like 

Apple  Grape  100
Ginger Fry    200
Apple  Grape  80
Ginger Banana 800
Ginger Fry    150
Ginger Banana 45

[download]

I want my output to be like this, where the duplicate data values are added

Apple  Grape  180
Ginger Fry    350
Ginger Banana 845

[download]

I am trying to do it using array of arrays but not able to proceed much.here is my code

#! /usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my @AoA;
open (my $fh ,"<","C:/excl7.txt") or die "Can't open the file";
while (<$fh>){
    #chomp ($line);
    push @AoA,[split];


}
foreach my $i (@AoA){
#** how do i compare the array data?...
    if (@{$i
    print "@$i\n";
}
#my @new =shift (@AoA);
#print $AoA[1][0];
#print Dumper \@AoA;

[download]
Is there other way which will be easier to do? plz help..thaanks in advance <

Replies are listed 'Best First'.
Re: Adding the duplicate data using arrays
by Ratazong (Monsignor) on Aug 11, 2010 at 07:31 UTC

    Why do you want to use an array? The natural thing when you hear duplicate or unique is to think of hashes.

    With that, use the following approach:

    • loop through the file line-by line
      • split the line into fruit-name and number (using a regex)
      • use the fruit-name as key for a hash and add the number (e.g. $fruits{$fruit_name} += $number;)
    • print the hash

    That's all. Not too hard, isn't it?! ;-)

    Rata
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Re: Adding the duplicate data using arrays
by biohisham (Priest) on Aug 11, 2010 at 07:49 UTC
    Just as Rata mentioned, a hash is more logical a solution in this case, a very simple hash approach can perform the job quite efficiently...

    how do i compare the array data?...
    Using a hash you don't have to compare data because all you need is just a hash key to hold all the data that belong to that type of fruit...

    Consider 
    use strict;
use warnings;
use Data::Dumper;
my %hash;
while(<DATA>){
    my ($key, $number)=split;
    $hash{$key} +=$number;
    }

print Dumper (\%hash);
__DATA__
apples 10
oranges 3
apples 3
oranges 7

    [download]

    Excellence is an Endeavor of Persistence. A Year-Old Monk :D .
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Re: Adding the duplicate data using arrays
by wwe (Friar) on Aug 11, 2010 at 07:46 UTC
    This should work as expected. I used hash of hashes, as it looks simpler for me: 
    #! /usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my %HoH;

while (<DATA>) {
    chomp $_;
    #print "<$_>\n";
    my ($lev1, $lev2, $amount) = (split /\s+/, $_);
    #print "<$lev1>, <$lev2>, <$amount>, \n";
    if (exists $HoH{$lev1}{$lev2}) {
        $HoH{$lev1}{$lev2} = $HoH{$lev1}{$lev2} + $amount;
    }
    else {
        $HoH{$lev1}{$lev2} = $amount;
    }
}

#print Dumper(\%HoH);

while (my ($lev1, $inter) = each %HoH) {
        while (my ($lev2, $amount) = each %$inter) {
            printf ("%-10s%-10s%-5d\n", $lev1,$lev2,$amount);
        }
}



__DATA__
Apple  Grape  100
Ginger Fry    200
Apple  Grape  80
Ginger Banana 800
Ginger Fry    150
Ginger Banana 45

    [download]
    prints on my system: 
    Ginger    Fry       350  
Ginger    Banana    845  
Apple     Grape     180

    [download]
    maybe you want to change formatting.
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