Hello monks, here is my question. I have 2 files, one containing a list of IDs that looks like this:

GSAD1234
GSAD2345
GSAD4567
[download]

And another one that looks like this, it is a csv with tab as field delimiter (which I symbolize here with " \t " as somehow I can't add a real tab here, also please note that I did not forget a tab in "no match", there are really fields that do contain white spaces):

GSAD1234 \t 123 \t 45 \t no match \t fungus \t protein_x
GSAD5678 \t 123 \t 51 \t plant \t fungus \t protein_y \t transporter
[download]

It is worth mentioning this second file contains more than 50 000 lines.

I would like to extract from the second file the lines corresponding to the IDs from the first file. So here the desired output would be:

GSAD1234 \t 123 \t 45 \t no match \t fungus \t protein_x
[download]

How do I do that? I had thought of reading the second file into a hash with the IDs as key and the rest of the fields as values but I can't find a way to do it due to the multiple fields per line. So far I have read the 2 files into arrays and tried to match the lines but it doesn't work and again, I am not sure it is the right strategy. Here is the code that seems to simply output the whole csv file:

#!/usr/bin/perl

use warnings;
use strict;
use Text::CSV;
use File::Slurp;


my $csv = Text::CSV->new({ sep_char => '\t' });
#end of preparation


#read data
my $file = $ARGV[0] or die "Need to get CSV file on the command line\n
+";

open(my $data,'<',$file) or die "Could not open file \n";
chomp (my @strings = <$data>);
close $data;

# read ID list

my $id = 'id.txt';
my @ids = read_file("$id", chomp =>1);
foreach(@ids) {
    my @matches = grep(/^($_)/,@strings);
    print join ",",@matches;
    }
[download]

I would be grateful for any help.

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