he can also use things like keys %{$hash{$store}} to list all products.
Agree. But does he need to?
neither shorter to write

It's shorter to write: "$h{$s,$p}" 9 characters. "$h{$s}{$p}" 10 characters. + code to populate hash is simpler.

nor more efficient

Maybe memory usage is not important in this case? And maybe serialization/deserialization time is more important. Who knows.

Also, perl has a special notation for it. That makes me think it's a useful feature for some cases.

In reply to Re^5: Possible for Map to create Hash of Hash? by vsespb
in thread Possible for Map to create Hash of Hash? by konnjuta

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