Here's a neat (I think so anyway) little trick that I found.
1) declare a hashref. ($hashref = {})
if you check to see if the hash is defined then
if(defined $hashref)
always returns true even if you have not added to the hash, however if you check for
if(defined %$hashref)
then this will only return true if $hashref actually refers to an existing hash. so I guess that
if(defined $hashref->{KEY})
should only return true if the key exists.

In reply to Re: Autovivification with hash of hashes by Anonymous Monk
in thread Autovivification with hash of hashes by Mr_Person

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