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how are the number of buckets in a perl hash chosenby david2008 (Scribe) 
on Jun 09, 2014 at 07:37 UTC ( #1089235=perlquestion: print w/ replies, xml )  Need Help?? 
david2008 has asked for the
wisdom of the Perl Monks concerning the following question:
Hi all,
I take now a refresher on algorithms with the coursera course https://class.coursera.org/algo005 given by Tim Roughgarden.
There is a whole week devoted to hash tables and bloom filters. He mentioned there that the numbers of buckets in a hash should be a prime number, which is not close to a power of 2 or 10. I use hashes in a perl on a daily basis and wanted to see how the theory is translated to the real world :). Firs i created a small hash %c= (a=>3,4=>5) and saw that the number of buckets are 8. Then i wrote a small code: and got the result 7391/16384. Apparently the number of buckets are not prime and are divided by two. I know from my experience that the perl hashes work amazingly fast and efficient. So how can this be explained? Thanks, David
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