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problem when hash value is null

Posted on 2007-11-27
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Last Modified: 2010-03-05
I am retrieving a resultset from the database and pushing the data to hash.

push @{$h{$data[1]}{$data[0]}{$data[2]}{$data[3]}},@data[4,5];

This works fine if the data in 4th and 5th field is not null. But if it is null. The hash is not retrieving the result. Please help
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Question by:saibsk
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LVL 39

Expert Comment

by:Adam314
ID: 20361442
What do you want to put in your hash when 4th and 5th fields are null?
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Author Comment

by:saibsk
ID: 20361483
I am writing the data to a file. So when the data fields 1, 0, 2, 3 are same I group them and the corresponding 4th and 5th values are written to a file. But when the 4th and 5th fields are null. That record from the result set is not being written to the file.  If the 4th and 5th fields are null I want to write empty strings with corresponsing 0,1,2,3 fields to the file.
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Expert Comment

by:shayne321
ID: 20361686
This would be one way:

$val1 = $data[4] || '';
$val2 = $data[5] || '';

push @{$h{$data[1]}{$data[0]}{$data[2]}{$data[3]}}, ($val1, $val2);

In this way if the 4th and 5th fields are undefined the "or" condition will evaluate to an empty string ('')
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Accepted Solution

by:
shayne321 earned 1500 total points
ID: 20361707
Or, without using temporary variables:

$data[4] = '' unless (defined $data[4]);
$data[5] = '' unless (defined $data[5]);
push @{$h{$data[1]}{$data[0]}{$data[2]}{$data[3]}},@data[4,5];
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Author Comment

by:saibsk
ID: 20361782
doesn't work. Problem still exists. Please advise.
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LVL 39

Expert Comment

by:Adam314
ID: 20361785
How are you writing the data to a file?  Post the code for that part of your program.
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Author Comment

by:saibsk
ID: 20361805
for my $key1 (sort keys %h) {      
      
            print FH "\n#Group $key1 Accounts\n";
                  for my $key0 (sort keys %{$h{$key1}}){
                  for my $key2 (sort keys % {$h{$key1}{$key0}}){
                        for my $key3 (sort keys % {$h{$key1}{$key0}{$key2}}){
                              #print "\@\$h{$key1}{$key0}{$key2}{$key3} = @{$h{$key1}{$key0}{$key2}{$key3}}\n";
                  
                  @arr = ($key0,$key1,$key2,$key3,@{$h{$key1}{$key0}{$key2}{$key3}});
            print FH join("\t,",@arr)."\n";
            }
      }
}
      print FH "\n";      
}
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LVL 39

Expert Comment

by:Adam314
ID: 20361862
push @{$h{$data[1]}{$data[0]}{$data[2]}{$data[3]}},[@data[4,5]];
0
 

Author Comment

by:saibsk
ID: 20365540
Doesn't seem to work
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Author Comment

by:saibsk
ID: 20365859
I had to make few changes to the resultset with that shayne321 solution works.
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