#!perl
use strict;
my @Stars = qw(CYP2C19_10 CYP2C19_12); 
return if (@Stars == 0);

# name,no
my $ref_file = "test.csv";
open my $star_FH,'<',$ref_file
   or die "Could not find reference file $ref_file : $!";

my %RSno=();
my $count=0;
print "Reading from ref_file $ref_file .. ";
while (<$star_FH>){      
  s/\s+$//;
  my ($no,$name) = split ",",$_;
  $RSno{$name}   = $no;
  ++$count;
}
close $star_FH;
print "$count records read\n";

for my $StarIndex (@Stars){
  if (exists $RSno{$StarIndex}){
    print "$StarIndex is $RSno{$StarIndex}\n";
  } else {
    print "$StarIndex NO CONVERSION\n";
  }
}