Hello!
You already has been provided with more than one way to do this, and I want to participate in this game too. Here's another way - just like you wanted - using map:
use strict;
my $weapons_ref = {
dagger => { cost => 8, damage => 4, armor => 0 },
shortsword => { cost => 10, damage => 5, armor => 0 },
warhammer => { cost => 25, damage => 6, armor => 0 },
longsword => { cost => 40, damage => 7, armor => 0 },
greataxe => { cost => 74, damage => 8, armor => 0 },
};
my $sum_cost;
my $sum_damage;
my $sum_armor;
map {
$sum_damage += $weapons_ref->{$_}->{damage};
$sum_cost += $weapons_ref->{$_}->{cost};
$sum_armor += $weapons_ref->{$_}->{armor}
} keys %{ $weapons_ref };
print join(' ',$sum_cost, $sum_damage, $sum_armor), '\n';
157 30 0
This code is a little bit specific, while I think we should move towards more general code, to make reusing it more simpler. Let's refactor it:
use strict;
use Data::Dumper;
my $weapons_ref = {
dagger => { cost => 8, damage => 4, armor => 0 },
shortsword => { cost => 10, damage => 5, armor => 0 },
warhammer => { cost => 25, damage => 6, armor => 0 },
longsword => { cost => 40, damage => 7, armor => 0 },
greataxe => { cost => 74, damage => 8, armor => 0 },
};
my $sum_result;
my @sum_fields = qw/cost damage armor/;
map {
my $name = $_;
map { $sum_result->{$_} += $weapons_ref->{$name}->{$_} } @sum_fields
} keys %{ $weapons_ref };
print Dumper($sum_result);
$VAR1 = {
'armor' => 0,
'cost' => 157,
'damage' => 30
};
Next step is to refactor this code to a function, which will receive a hash, an array of fields that we like to sum, and return a hash with sums.