Oh I see, the '' is the stringified undef. Yes, that I appreciate, but

however, %hash=undef=>undef; may not do what you mean, if you don't know what you mean. here, the difference between , and => is plain.

Boy, did I sound *that* clueless? I was just verifying the various somevariable = undef behavior before I post an answer, and just came upon one that seemed weird strange. ugh.