Count occurrences in MultiMap

Question

I have a MultiMap that has multiple similar values:

{Entertainment=[5], Food=[2, 2, 2], Products=[11], Health & Beauty=[3]}

How do I count the total of these keys so that it counts as follows?

Entertainment = 1
Food = 3
Products = 1
Health & Beauty = 1

The number inside the array is the category id, so that Food has 3 occurrences.

Answer 1

Either multimap.get(key).size() or multimap.keys().count(key) should work.

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