# main sub 
{ # closure 
# keep %species local to sub-routine but only init it once 
my %species; 
sub _init { 
    open my $in, '<', 'SpeciesId.txt' or die "could not open SpeciesId.txt: $!"; 
    my $spec; 
    while (<$in>) { 
        chomp; 
        next if /^\s*$/; # skip blank lines 
        if (m{^([A-Z])\s*=\s*(\d+(?:\.\d)?)(?:\s+AND\s+(\d+(?:\.\d)?))?$}) { 
            # handle letter = lines 
            $species{$spec}{$1} = [$2]; 
            push @{$species{$spec}{$1}}, $3 if $3; 
        } else { 
            # handle species name lines 
            $spec = $_; 
            $len = length($spec) if (length($spec) > $len); 
        } 
    } 
    close $in; 
} 
sub analyze { 
    my ($masses) = @_; 
    _init() unless %species; 
    my %data; 
    # loop over species entries 
SPEC: 
    foreach my $spec (keys %species) { 
        # loop over each letter of a species 
LTR: 
        foreach my $ltr (keys %{$species{$spec}}) { 
            # loop over each mass for a letter 
            foreach my $mass (@{$species{$spec}{$ltr}}) { 
                # skip to next letter if it is not found 
                next LTR unless exists($masses->{$mass}); 
            } 
            # if we get here, all mass values were found for the species/letter 
            $data{$spec}{cnt}++; 
        } 
    }