From: Chuck Remes <cremes.devlist@...>
Date: 2009-07-21T22:28:11+09:00
Subject: Re: Mean method


On Jul 21, 2009, at 7:41 AM, Älphä Blüë wrote:

> I'm working on a lot of math in my projects so I thought I would  
> convert
> over a few methods I used in other languages that I created and port
> them to ruby.
>
> Here's a mean method which allows you to return either:
>
> a) arithmetic mean
> b) geometric mean
> c) harmonic mean
>
> http://pastie.org/553287

The pastie is missing your extension of Array to add the #sum method,  
so the example doesn't work. Also, unless #sum returns a float then it  
is possible for your arithmetic mean to return a result truncated to  
the nearest integer due to the way Ruby's division works with integers.

Lastly, I have a style suggestion. In your parameter sanity checks, I  
think this reads easier:

raise "mean(#{an_array}) error: #{an_array} is not an array." unless  
an_array.is_a? Array

raise "mean(#{an_array},#{i_type}) error:: #{i_type} mean type is not  
an integer." unless i_type.is_a? Fixnum

raise "mean(#{an_array},#{i_type}) error: invalid mean type  
((#{i_type}) set. Only 1..3 valid." unless (1..3).include? i_type

Thanks for sharing your code.

cr