Count array index

Hi, first sorry for my English. I have a little problem with counting how many times index appear in a array/// for example: 0-dog,1-dog, 2-dog, 3-cat, so final number of dogs is a three and cats is a one.

If someone have answer i will happy to read it/see a capx...

P.S I have run a search but find nothing (there are tons of data here so maybe i miss the answer)

Here's a quick example.

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Many thanks Minor