On Thu, Feb 06, 2003 at 10:56:06AM -0500, Joel Gwynn wrote:
> Wow. This is driving me crazy. I'm looking for a value in one of the
> keys in a hash, like so:
[...]
> Now, what's driving me crazy is that the two test values are being added
> to the hash, simply by looking for $apples{$t}{weight}. If I simply
> look for $apples{$t}, like so:
>
> foreach my $t (@test){ print "$t not found\n" unless $apples{$t} }
>
> new hash members are not created. Why should this be?
Uri Guttman wrote an excellent paper on Perl's autovivification:
http://tlc.perlarchive.com/articles/perl/ug0002.shtml
It includes some sample code to check for hash keys at any
level of a multi-level data structure without triggering
autovivification. (paraphrased from description in article)
-E
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