in reply to hash of arrays or separate hashes?

Hash keys always have to be unique, but there might be a way around your problem by restructuring your data. The value could be a hashref containing keys that store the count and the array:

Alpha => { count => 37, data => [0,0,4,26,0,7], }, Beta => { count => 40, data => [1,38,0,0,0,1], }, Gamma => { count => 3, data => [1,1,0,0,0,1], },

Notice that data in each hashref contains an arrayref, which is proably what you want (the orginal you posted would have made a hashref).

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: () { :|:& };:

Note: All code is untested, unless otherwise stated