my @files = ('tab1.txt','tab2.txt');

# Or, using the "quote-word" function "qw",
# which lets you omit the quotes and the comma:

my @files = qw( tab1.txt tab2.txt );

##</code><code>##

    my $hash_key =~ s/\.txt//; # generate hash key

##</code><code>##

Use of uninitialized value in substitution (s///) at merge.pl line 16.

##</code><code>##

    (my $hash_key = $file) =~ s/\.txt//; # generate hash key

##</code><code>##

$ptables{$hash_key} = [ @string_array ]; # save all strings to the hash
print Dumper(\%ptables);                 # use "\" to pass reference of hash