That is not exactly the same thing.
But it depends on your specs.
class Array
def spread(num)
res,idue = ,
(1..(size-num)).each{|u| idue << size*u/(size-num+1)}
(0...size).each{|y| res << self[y] if idue.include?(y) == false}
res
end
def spread2(num)
discarded =
(1..(size-num)).each{|u| discarded << self[size*u/(size-num+1)]}
self - discarded
end
end
arr = [1,2,3,4,5,6,7,8,9,9,10,11,12]
(3..13).each{|t| p arr.spread(t)}
puts
(3..13).each{|t| p arr.spread2(t)}
############output
#=> [1, 7, 12]
#=> [1, 5, 9, 12]
#=> [1, 4, 7, 9, 12]
#=> [1, 3, 6, 8, 10, 12]
#=> [1, 3, 5, 7, 9, 10, 12]
#=> [1, 2, 4, 6, 8, 9, 11, 12]
#=> [1, 2, 4, 5, 7, 9, 9, 11, 12]
#=> [1, 2, 3, 5, 6, 8, 9, 10, 11, 12]
#=> [1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12]
#=> [1, 2, 3, 4, 5, 6, 8, 9, 9, 10, 11, 12]
#=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10, 11, 12]
#=> [1, 7, 12]
#=> [1, 5, 12]
#=> [1, 4, 7, 12]
#=> [1, 3, 6, 8, 10, 12]
#=> [1, 3, 5, 7, 10, 12]
#=> [1, 2, 4, 6, 8, 11, 12]
#=> [1, 2, 4, 5, 7, 9, 9, 11, 12]
#=> [1, 2, 3, 5, 6, 8, 10, 11, 12]
#=> [1, 2, 3, 4, 6, 7, 8, 10, 11, 12]
#=> [1, 2, 3, 4, 5, 6, 8, 9, 9, 10, 11, 12]
#=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10, 11, 12]
Harry
···
On Wed, Sep 2, 2009 at 5:30 PM, Max Williams<toastkid.williams@gmail.com> wrote:
Thanks, everyone. Harry, i like your solution but i thought of a way to
tweak it in a way which seems more readable, to me at least:
class Array
def spread(num)
discarded =
(1..(size-num)).each{|u| discarded << self[size*u/(size-num+1)]}
self - discarded
end
end
The clever bit is of course line 4. I'm still trying to work out why
that works 
--
A Look into Japanese Ruby List in English
