Question

This is a simple problem but cannot find any working solution for it. I have 2 files and the first file holds all the ID that I am interested in, for example “tomato”, “cucumber”, but also the ones I am not interested in, which hold no value in the second file. The second file has the following data structure

tomato    red

tomato    round

tomato    sweet

cucumber    green

cucumber    bitter

cucumber    watery

What I need to get is a file containing all the IDs with all the matching values from the second file, everything tab-seperated, like this:

tomato    red    round    sweet

cucumber    green    bitter    watery   

What I did so far is create a hash out of the IDs in the first file:

 while (<FILE>) {  
     chomp;  
     @records = split "\t", $_; 
     {%hash = map { $records[0] => 1 } @records};
 }

And this for the second file:

  while (<FILE2>) {
      chomp;
      @records2 = split "\t", $_; 
      $key, $value = $records2[0], $records2[1];
      $data{$key} = join("\t", $value);
  }

 close FILE;

 foreach my $key ( keys %data )
 {
     print OUT "$key\t$data{$key}\n"
     if exists $hash{$key} 
 }

Would be grateful for some simple solution for combining all the values matching the same ID! 🙂

Answer 1

for th first file:

while (<FILE>) {  
    chomp;  
    @records = split "\t", $_; 
    $hash{$records[0]} = 1;
}

and for the second:

while (<FILE2>) {
    chomp;
    @records2 = split "\t", $_;
    ($key,$value) = @records2;
    $data{$key} = [] unless exists $data{$key};
    push @{$data{$key}}, $value;
}
close FILE;

foreach my $key ( keys %data ) {
    print OUT $key."\t".join("\t", @{$data{$key}})."\n" if exists $hash{$key};
}