Question

I have a situation like this: I have a file like file1

file1

List      ID 
1         NM_00012  
2         NM_00013   
2         NM_00013
3         NM_00021  
3         NM_00021
4         NM_000254
5         NM_000765

and a second file that looks like this:

file2

List      Count 
1         Gene1 
2         Gene2
2         Gene2
3         Gene3 
3         Gene3 
4         Gene4
5         Gene5

I would like the following output:

file 3

List       Count 
NM_00012   Gene1    
NM_00013   Gene2        
NM_00021   Gene3                
NM_000254  Gene4        
NM_000756  Gene5          

Can anyone help me?
I’m totally new in Perl.

Thanks in advance!!

Answer 1

You can something like (not tested):

my (%hash1, %hash2, $list, $count, $ID);
open F,"<","file2.txt" or die;
while(<F>) {
  chomp;
  ($list,$count) = split/\s+/;
  $hash1{$list} = $count;  
}
close F;

open F,"<","file1.txt" or die;
while(<F>) {
  chomp;
  ($list,$ID) = split/\s+/;
  if(! exits $hash2{$ID}) {
    print "$ID $hash1{$list}";
    $hash2{$ID} = 1;
  }
}
close F;