Well, yes it's possible to do it using something like your approach. Your file_merge() subroutine would look like this:

sub file_merge {
  my $hash_ref = shift;
  while (<>) {
    chomp;
    my ($key, @values) = split /-/, $_;
    push @{$hash_ref->{$key}}, [ @values ];
  }
}
[download]

But actually, that's not right as you're reading from the default filehandle each time.

I'd do this completely differently.

sub file_merge {
  my $filename = shift;

  open my $fh, '<', $filename
    or die "$filename: $!\n;

  my %hash;
  while (<$fh>) {
    chomp;
    my ($key, @values) = split /-/, $_;
    push @{$hash{$key}}, [ @values ];
  }

  return %hash;
}
[download]

You would then call it like this:

my %msisdn = file_merge('/tmp/subscription_list');
my %calls  = file_merge('/tmp/Call_Det');
[download]

Another (perhaps better) alternative would be to return a hash reference rather than a hash.

As always strict and warnings will point out some of the major problems with your code.

yeah this is much better option rather than passing hash as the argument. But the file hadle in the sub function has to be closed i suppose.

But the file hadle in the sub function has to be closed i suppose.

The filehandle is a lexical variable. It will be closed automatically as the variable goes out of scope (i.e. as the subroutine is exited).

--


See the Copyright notice on my home node.

Perl training courses

Did you try it with use strict; use warnings;?

Either would give you some significant hints.

yeah i though i will first do with the logic and then use the strict and warning module.

Wrong!

As your code demonstrates, doing the logic avails nothing if the syntax is wrong. Use strict and warnings as intended -- as helpers -- to get the syntax right, so you can tell if the algorithm you've selected|developed\whatever produces what you intended.

If your code won't compile, you'll never know if you've got the logic right.

A minor change to your code...

my %MSISDN=();

#populate the subscription list to hash MSISDN

        open(FILE,"/tmp/subscription_list") || die "Unable to open sub
+scription file";
        %MSISDN = %{ file_merge(\%MSISDN) };
        close(FILE);

my  %Calls=();

#populate the usage types to hash Calls

       open(FILE1,"/tmp/Call_Det")|| die "Unable to open call_details 
+file";
       %Calls = %{ file_merge(\%Calls) };
       close(FILE1);
}

sub file_merge
{
## take from @_ (the args passed to the subrtn)
my $hash_ref = shift; 
while (<>) {
  chomp;
  my ($key, @values) = split /-/, $_;
  push @{$hash_ref{$key}}, [ @values ];
}
return $hash_ref;
}
[download]

But you would be better off passing in the filepath, doing the reading and parsing in your sub and passing back the hash ref... see below by davorg...

You're reading from the wrong filehandle (a bug you inherited from the original code).

--


See the Copyright notice on my home node.

Perl training courses

Sorry - didn't run the code, just tried to change the bit they asked about... lesson learned...

Just a something something...