How do I remove duplicate characters and keep the unique one only in Perl?

Question

How do I remove duplicate characters and keep the unique one only. For example, my input is:

EFUAHUU
UUUEUUUUH
UJUJHHACDEFUCU

Expected out

Answer 1

Tie::IxHash is a good module to store hash order (but may be slow, you will need to benchmark if speed is important). Example with tests:

use Test::More 0.88;

use Tie::IxHash;
sub dedupe {
  my $str=shift;
  my $hash=Tie::IxHash->new(map { $_ => 1} split //,$str);
  return join('',$hash->Keys);
}

{
my $str='EFUAHUU';
is(dedupe($str),'EFUAH');
}

{
my $str='EFUAHHUU';
is(dedupe($str),'EFUAH');
}

{
my $str='UJUJHHACDEFUCU';
is(dedupe($str),'UJHACDEF');
}

done_testing();