in reply to Re^2: Load a file into hash with duplicate keys
in thread Load a file into hash with duplicate keys

Show us the input file Table1.txt.
Here you are splitting the input line based on tab delimiter and collecting the first element[0] in  $key 
my $key = (split/\t/, $line)[0];

[download]
Here you are pushing every line that has the same key into an array 
push @{ $hash{$key} }, $line;

[download]
There can only be unique keys in such a data structure. UPDATE 
while(<DATA>)
{
   chomp;
   my $line = $_;
   
   my $key = (split/\s+/, $line)[0];
   push @{ $hash{$key} }, $line;
}

print Dumper(\%hash);

__DATA__
NM_001127328    202502_at
NM_000018    200710_at
NM_000019    205412_at
NM_001111067    203935_at
NM_000023    210632_s_at
NM_000027    204332_s_at
NM_000027    204333_s_at
NM_000027    216064_s_at
NM_000029    202834_at
NM_000031    218487_at
NM_000031    218489_s_at
NM_000032    211560_s_at
NM_000036    206121_at
NM_000042    205216_s_at
NM_000043    204780_s_at
NM_000043    204781_s_at
NM_000043    215719_x_at
NM_000043    216252_x_at
NM_000044    211110_s_at
NM_000044    211621_at

[download]
prints... 
$VAR1 = {
          'NM_000032' => [
                           'NM_000032    211560_s_at'
                         ],
          'NM_000044' => [
                           'NM_000044    211110_s_at',
                           'NM_000044    211621_at'
                         ],
          'NM_001111067' => [
                              'NM_001111067    203935_at'
                            ],
          'NM_000023' => [
                           'NM_000023    210632_s_at'
                         ],
          'NM_001127328' => [
                              'NM_001127328    202502_at'
                            ],
          'NM_000031' => [
                           'NM_000031    218487_at',
                           'NM_000031    218489_s_at'
                         ],
          'NM_000043' => [
                           'NM_000043    204780_s_at',
                           'NM_000043    204781_s_at',
                           'NM_000043    215719_x_at',
                           'NM_000043    216252_x_at'
                         ],
          'NM_000029' => [
                           'NM_000029    202834_at'
                         ],
          'NM_000042' => [
                           'NM_000042    205216_s_at'
                         ],
          'NM_000019' => [
                           'NM_000019    205412_at'
                         ],
          'NM_000018' => [
                           'NM_000018    200710_at'
                         ],
          'NM_000027' => [
                           'NM_000027    204332_s_at',
                           'NM_000027    204333_s_at',
                           'NM_000027    216064_s_at'
                         ],
          'NM_000036' => [
                           'NM_000036    206121_at'
                         ]
        };

[download]

Replies are listed 'Best First'.
Re^4: Load a file into hash with duplicate keys
by sophix (Sexton) on Nov 02, 2010 at 20:54 UTC

    As AnonymousMonk suggested, I used the second colum as the key.

    #!/usr/bin/perl -w
use Data::Dumper;

my $data = '/Data/Table1.txt'; 
open INFILE, '<', $data or die "aa\n";

my %hash = map { chomp; split /\t/ } <INFILE>;
print Dumper(\%hash);

my $data2 = '/Data/Table2.txt'; 
open INFILE2, '<', $data2 or die "aa\n";

my %hash2;
while(<INFILE2>)
{
   chomp;
   my $line = $_;
   
   my $key = (split/\t/, $line)[0];
   push @{ $hash2{$key} }, $line;
}

print Dumper(\%hash2);

    [download]

    This returns the following output

    $VAR1 = {
          '218489_s_at' => 'NM_000031',
          '216064_s_at' => 'NM_000027',
          '218487_at' => 'NM_000031',
          '211110_s_at' => 'NM_000044',
          '204333_s_at' => 'NM_000027',
          '210632_s_at' => 'NM_000023',
          '203935_at' => 'NM_001111067',
          '211560_s_at' => 'NM_000032',
          '204332_s_at' => 'NM_000027',
          '215719_x_at' => 'NM_000043',
          '204780_s_at' => 'NM_000043',
          '202834_at' => 'NM_000029',
          '206121_at' => 'NM_000036',
          '204781_s_at' => 'NM_000043',
          '205412_at' => 'NM_000019',
          '216252_x_at' => 'NM_000043',
          '205216_s_at' => 'NM_000042',
          '211621_at' => 'NM_000044',
          '200710_at' => 'NM_000018',
          '202502_at' => 'NM_001127328'
        };
$VAR1 = {
          '211560_s_at' => [
                             '211560_s_at       P       P       P     
+  A
P       P       P'
                           ],
          '204332_s_at' => [
                             '204332_s_at       P       P       A     
+  P
P       P       P'
                           ],
          '216064_s_at' => [
                             '216064_s_at       P       M       P     
+  P
P       A       A'
                           ],
          '200005_at' => [
                           '200005_at   P       P       A       P     
+  P
P       A'
                         ],
          '211110_s_at' => [
                             '211110_s_at       P       A       P     
+  A
P       A       P'
                           ],
          '200003_s_at' => [
                             '200003_s_at       P       A       P     
+  P
P       A       P'
                           ]
        };

    [download]

    The first value elemant in the second hash includes the key.

[reply]
[d/l]
[select]
          my $key = (split/\t/, $line)[0];
    push @{ $hash2{$key} }, $line;

      [download]
      Try this instead: 

          my ($val, $key) = split /\t/, $line;
    push @{ $hash2{$key} }, $val;

      [download]
[reply]
[d/l]
[select]
        sorry, meant the other way round: 

            my ($key, $val) = ...

        [download]
[reply]
[d/l]

        I think you meant this:

          my ($key, $val) = split /\t/, $line;
    push @{ $hash2{$key} }, $val;

        [download]

        In this case, it only stores the first value.

        $VAR1 = {
          '211560_s_at' => [
                             'P'
                           ],
          '204332_s_at' => [
                             'P'
                           ],
          '216064_s_at' => [
                             'P'
                           ],
          '200005_at' => [
                           'P'
                         ],
          '211110_s_at' => [
                             'P'
                           ],
          '200003_s_at' => [
                             'P'
                           ]
        };

        [download]
[reply]
[d/l]
[select]

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