http://qs321.pair.com?node_id=340027

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

Monks
I have an inventory (textfile) with the following:
Category ID Name Type Size
=======================================
WaterSports 8765 Drysuit r M-L
WaterSports 8365 Paddle t 45
…
WinterSports 5231 Snowboard j 85
WinterSports 5281 Gloves r S
Etc..
I want to create a hash of hashes like the following
$VAR1 = {
          'WaterSports' => [
                          '8765',
                          [
                            'Drysuit',
                            'r',
                            'M-L'
                          ]
                          '8365',
                          [
                            'Paddle',
                            't',
                            '45'
                          ]
                        ]
        };

[download]
But instead my code is creating this, what is wrong?
$VAR1 = {
      'WaterSports' => [
                          '8765',
                          [
                            'Drysuit',
                            'r',
                            'M-L'
                          ]

        };
$VAR1 = {
          'WaterSports'=> [
                          '8365',
                          [
                            'Paddle',
                            't',
                            '45'
                          ]
                    ]
        };

[download]
This is my code: 
open(INFILE, "products-id.txt")|| die "Cannot open products-id.txt fil
+e"; 
open (OUTPUT,">$output") or die ("Can't open file $output $!");

chomp(my @ProductArray = map { /^\s*$/ ? () : $_ } <INFILE>);
close (INFILE);

foreach my $line(@ProductArray)
{
  my ($Category, $ID, $Name, $Type, $Size) = split( / /, $line );

  %AllProducts = ($Category => [$ID, [$Name, $Type, $Size]]);

print OUTPUT Dumper(\%AllProducts);

}

[download]
Thanks is advance!!

Replies are listed 'Best First'.
Re: Different hashes?
by Fletch (Bishop) on Mar 26, 2004 at 14:58 UTC

    You're clearing out the entire hash each time through the loop and replacing it with new contents. You want push @{ $AllProducts{ $Category } }, [ $ID, [ $Name, $Type, $Size ] ]. See perldoc perlreftut, perldoc perldsc, and perldoc perllol.

[reply]
[d/l]
[select]

      Fletch and borisz:
      the outer array referencing brackets [ ] are still wrong, take them away and you got it right.

[reply]

        Actually what he probably really wants is a HOH and should be doing something like: 

        $AllProducts{ $Category }->{ $ID } = { name => $Name, type => $Type, s
+ize => $Size };

        [download]

        But that's why he should read perldoc perldsc.

[reply]
[d/l]
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Re: Different hashes?
by tcf22 (Priest) on Mar 26, 2004 at 15:04 UTC
    You are overwriteing the key in %AllProducts every loop. You need to make the hash value an array ref then push onto it.

    Try this: 
    foreach my $line(@ProductArray)
{
  my ($Category, $ID, $Name, $Type, $Size) = split( / /, $line );

  unless(exists $AllProducts{$Category}){
    $AllProducts{$Category} = [];
  }
  push(@{$AllProducts{$Category}}, $ID, [$Name, $Type, $Size]);

  print OUTPUT Dumper(\%AllProducts);
}

    [download]

    - Tom

[reply]
[d/l]
Re: Different hashes?
by borisz (Canon) on Mar 26, 2004 at 15:07 UTC 
    #!/usr/bin/perl
use Data::Dumper;
my %products;
while (defined( $_ = <DATA> )){
  next if $. <= 2 || /^\s*$/;
  my @d   = split ' ';
  my $cat = shift @d;
  my $id  = shift @d;
  push @{$products{$cat}}, [ $id, \@d ];
}
print Dumper(\%products);
__DATA__
Category ID Name Type Size
=======================================
WaterSports 8765 Drysuit r M-L
WaterSports 8365 Paddle t 45
WinterSports 5231 Snowboard j 85
WinterSports 5281 Gloves r S

    [download]
    Boris
[reply]
[d/l]
Re: Different hashes?
by Happy-the-monk (Canon) on Mar 26, 2004 at 15:03 UTC

    Make the following change to your code:

    -    %AllProducts = ($Category => [$ID, [$Name, $Type, $Size]]);
    +    push @{ AllProducts{$Category} }, ( $ID, [$Name, $Type, $Size] );

    what was wrong?

    1. redefined the hash while looping, thus overwriting it.
    2. made a new array reference instead of pushing onto it.

    Cheers, Sören

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[d/l]
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Re: Different hashes?
by Anonymous Monk on Mar 26, 2004 at 15:36 UTC
    Thank you Monks and thanks for you comments!! It is working now :)
[reply]
Different hashes part II
by Anonymous Monk on Mar 26, 2004 at 16:29 UTC
    Hello Monks I just send a message not long ago (different hashes?), and I tried your suggestions. I thought it was working because I run the script with a small textfile, but it is not!! :(
    It is creating a new hash, adding a new record at the time. it's exponential huge
    $VAR1 = {
      'WaterSports' => [
                          '8765',
                          [
                            'Drysuit',
                            'r',
                            'M-L'
                          ]

        };
$VAR1 = {
          'WaterSports'=> [
                          '8765',
                          [
                            'Drysuit',
                            'r',
                            'M-L'
                          ]
                         '8365',
                          [
                            'Paddle',
                            't',
                            '45'
                          ]

                    ]
        };

    [download]
    This is my modify code: 
    open(INFILE, "products-id.txt")|| die "Cannot open products-id.txt fil
+e"; 
open (OUTPUT,">$output") or die ("Can't open file $output $!");

chomp(my @ProductArray = map { /^\s*$/ ? () : $_ } <INFILE>);
close (INFILE);

foreach my $line(@ProductArray)
{
  my ($Category, $ID, $Name, $Type, $Size) = split( / /, $line );

  push(@{$AllProducts{$Category}}, $ID, [$Name, $Type, $Size]);

print OUTPUT Dumper(\%AllProducts);

}

    [download]
    I also tried this 
      push @{$AllProducts{$Category}}, ($ID, [$Name, $Type, $Size]);

    [download]
    Thanks
[reply]
[d/l]
[select]
      I am trying borisz's solutions, but as well as the others it's taking too much time to execute, so I cancelled it.. but this time the PARTIAL output I am getting is OK, I am not sure it is repeating the whole thing over and over.. 
      Borisz's script:
#!/usr/bin/perl
use Data::Dumper;
my %products;
while (defined( $_ = <DATA> )){
  next if $. <= 2 || /^\s*$/;
  my @d   = split ' ';
  my $cat = shift @d;
  my $id  = shift @d;
  push @{$products{$cat}}, [ $id, \@d ];
}
print Dumper(\%products);

      [download]
[reply]
[d/l]
        It is OK, I should not print the dumper(\%product) to the output file, inside the loop mmmmmm sorry about that
[reply]
      It might have been better to make this a reply or update to your earlier post. Since you seemed to have missed the point of advice that others gave there, I think I'll post a reply there myself, because more information is available there regarding the problem. (In fact, maybe the present thread should be "considered" for removal or relocation.)
[reply]

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