Course of Raku / Addendum 🆕 / Working with data / Lists, arrays, and hashes / Exercises / Merge two inventories

Solution: Merge two inventories

Here is a possible solution to the task.

Code

my %shop-a = apples => 3, pears => 2;
my %shop-b = apples => 4, plums => 5;

my %total;
for %shop-a, %shop-b -> %shop {
    %total{$_} += %shop{$_} for %shop.keys;
}

say %total.sort.map({ "{.key}: {.value}" }).join(', ');

🦋 You can find the source code in the file merge-inventories.raku.

Output

apples: 7, pears: 2, plums: 5

Comments

1. Looping over both hashes and doing %total{$_} += ... adds each quantity into the running total, whether or not the key was seen before — a missing key starts at zero.

2. %total.sort orders the pairs by key, and the .map formats each as key: value before they are joined.

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