Look into the Memoize function, which can remember the results of prior queries to speed it up. First, break out the lookup into a separate function: 
sub lookup {
  die unless wantarray; # call me in list context only
  my $item = shift;
  return values %{$EMail{$item}} if exists $EMail{$item}; # category n
+ame
  for my $cat (keys %EMail) {
    return $EMail{$cat}{$item} if exists $EMail{$cat}{$item}; # single
+ name
  }
  return; # not found
}
sub GetEmailFor {
  my @results = map { lookup($_) } @_;
  return join ",", @results;
}

[download]
This should be equivalent code (and quite faster, I might add {grin}). Now, let's speed it up further: 
use Memoize;
memoize('lookup');
sub I_have_changed_EMail {
  unmemoize('lookup');
  memoize('lookup');
}

[download]
and be sure to call I_have_changed_EMail any time you change your dataset (none at all if you "set it and forget it", as you indicate already).

There. Speed without too much work.

-- Randal L. Schwartz, Perl hacker

In reply to Re: Complex Hash by merlyn
in thread Complex Hash by Adam

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