This doesn't address the interesting questions you've raised about hashes. I'm sure that others will have good explanations of that, but I just wanted to point out that the best way to check if a hash contains any data is to use the keys function. In scalar context keys will return the number of keys defined in the hash.

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In reply to Re: Test Presence of Data in Hash by davorg
in thread Test Presence of Data in Hash by bichonfrise74

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