From: Chris Lowis <chris.lowis@...>
Date: 2007-02-20T19:29:05+09:00
Subject: Re: Help with Class design

Thank you all for your help, knowing exactly what "self" refers to in 
each context seems to be the stumbling block for me at the moment. I'll 
have to read about this some more, along with the documentation for some 
of the Enumerables .

> I suppose that you variance method should read something like
> 
>    def variance
>       m = mean
>       @signal.inject(0) { |sum, x| sum + (x-m)**2 } / @signal.length
>    end
> 
> Note that I prefer not using meaningless assignment in the inject block.

And to that end, using the suggestions above, I suppose I could equally 
well write :

  def variance()
    @signal.inject(0) { |var, x| var += (x - mean) ** 2 } / 
(@signal.length-1)
  end

removing the assignment "m = mean" ?



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