Memory consumption of an array of size X is the space needed for X pointers (more specific SV pointers) plus a SV for the array itself. A hash needs both the pointer, a key and some overhead for a linked list (the buckets) and itself.

Given you can program you program with little or no effort using arrays instead of hashes do just that. But if you need to use a lot of time rewriting something to use an array instead of a hash, use the hash.

PS.
OO is NOT better... Its just another way of doing things.
Personally I dont see the big point, when you are not 20+ people working on the same project...

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