From: Daniel Baird <danielbaird@...>
Date: 2006-08-02T16:22:39+09:00
Subject: golfing Eratosthenes

Hi all,

I've been golfing around with the sieve of Eratosthenes.  Here's what
I've got so far:

a=(2..100).to_a;p a.each{|c|a.map!{|d|c&&d&&c<d&&d%c==0?nil:d}}.compact

It's already under 80 chars, but I'd still love to remove the
definition of the array a, and do the whole thing with no semicolons.
Any suggestions?

If you're interested, here's an indented/commented copy that might
save a few minutes..

# create an array of integers, 2 to 100
a=(2..100).to_a;
p a.each{ |c|
  # for each element c in that array, if c isn't nil, it's prime. so
set multiples of c to nil
  a.map!{ |d|
    c && d && c<d && d%c == 0 ? nil : d
  }
}.compact  # finally, print the array minus the nils


I'd appreciate any comments.

Cheers

;Daniel


-- 
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