use List::Util 'first'; # Precompile all the patterns and store them into the key # CompiledPattern $_->{'CompiledPattern'} = qr/$_->{'Pattern'}/i for values %$users; my %unmatched_users; @unmatched_users{ keys %$users } = (); while ( my $line = <> ) { ... my $user = first { $line =~ $users->{$_}{'CompiledPattern'} } keys %unmatched_users; if ( defined $user ) { warn "Great, we found pattern $user->{'Pattern'}!\n"; delete $unmatched_users{ $user }; } else { warn "$line didn't match any users.\n"; } }