Hi there

I would like to do the following in perl:

Create a 2D matrix that gives an indication of how many people have two different animals in their home and what animals they are.

A 2D matrix - with the x axis labelled as 'cat', 'dog'. 'fish', 'rabbit'.

and also the y axis labelled 'cat', dog', 'fish, 'rabbit'.

and then - for example, if someone has a fish and a cat,  the numeric counter in the square than corresponds to the hit 'fish' on one axis and 'cat' on the other goes up by one.

Any suggestions as how I might go about doing this would be much appreciated.

Perl uses autovivification - where lists and hashes are set up automatically when you refer to them. Thus, just write

$pets{cat}{fish}++;

if you find a person with both a cat and a fish.

One suggestion - sort the two pet types alphabetically so that you don't have different entries for someone who says they have a cat and a fish to someone who says they have a fish and a cat.

And one thought. What do you want to do about someone with 3 different pets?

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