Hi all, I take now a refresher on algorithms with the coursera course https://class.coursera.org/algo-005 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: 
use strict;
use warnings;

my %h;

foreach my $i (0..10000) {
$h{$i} = $i+10;
}

my $j = %h;
print "$j";

[download]
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

In reply to how are the number of buckets in a perl hash chosen by david2008

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