From: Paul Smith <paul@...>
Date: 2009-09-25T22:10:19+09:00
Subject: Re: Roulette & rand

On Fri, Sep 25, 2009 at 1:26 PM, Semih Ozkoseoglu
<ozansemih@hotmail.co.uk> wrote:
> Hi again,
>
> I stumbled upon another interesting problem while I was playing with the
> code that I mentioned above.
>
> After the simple roulette code sorted (thanks to everyone who has
> responded) I tried to write a code where the bet was decided by another
> random roll. Suddenly the code started to loose twice it was loosing
> before.
>
> Now correct me if I'm wrong but shouldn't I always loose around 1/37 of
> the time; no matter how I decide to bet on what color?
>
> I don't know if there is something wrong with my code or with my logic
> and I welcome any suggestions. Again I'm sure its not the most important
> problem but I'm just curious  why this might be happening.
>
> Thanks for reading and here is the code that I put together so far (i
> tried to compare only betting red to betting randomly)
>
>
> colors = {}
> [2, 4, 6, 8, 10, 11, 13, 15, 17, 20, 22, 24, 26, 28, 29, 31, 33,
> 35].each do |i|
>  colors[i] = :black
> end
> [1, 3, 5, 7, 9, 12, 14, 16, 18, 19, 21, 23, 25, 27, 30, 32, 34, 36].each
> do |i|
>  colors[i] = :red
> end
>  colors[0] = :zero
>
> bet_rand = 0
> bet_red = 0
>
> puts 'How many rolls to simulate'
> number_of_rolls = gets.chomp.to_i
>
> number_of_rolls.times do
>
>  number_01 = rand(37)
>  color_01 = colors[number_01]
>  number_02 = rand(37)
>  color_02 = colors[number_02]
>
>  if color_01 == :red
>    bet_red += 1
>  else
>    bet_red -= 1
>  end
>
>  if color_02 == color_01
>    bet_rand += 1
>  else
>    bet_rand -= 1
>  end
> end
>
> puts bet_rand
> puts bet_red
> --
> Posted via http://www.ruby-forum.com/.
>
>

One problem that I can see is that you're allowing your random betting
strategy to pick 0, rather than red or black, which I don't think is
your intention.

Change

>  number_02 = rand(37)
>  color_02 = colors[number_02]

to

color_02 = [:red, :black][rand(2)]

maybe?

-- 
Paul Smith
http://www.nomadicfun.co.uk

paul@pollyandpaul.co.uk