Autovivification (or autovivication in some peoples lexicon) is a pretty well known feature of Perl. But we all walk slap bang into it at some time!

In the very same thread that Roger referred you to their is a nifty little subroutine ( Re: Autovivification with hash of hashes ) that you can use to test for existence without autovivifying the shallower levels of the hash. You will also find here a discussion of the subject and some more code that is related to the problem.

The subject is covered in detail in Programming Perl 3rd edition on page 254.

jdtoronto

In reply to Re: deleting a hash key can create one? by jdtoronto
in thread deleting a hash key can create one? by zentara

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