From: Florian Frank <flori@...>
Date: 2009-11-22T23:49:46+09:00
Subject: Re: really crazy about this (do/while)

David Masover wrote:
> So my compromise is, when I want to work with some fraction of a number, and I 
> want it to be as precise as possible (with no regard for performance), I make 
> it a Rational as long as I can get away with. I can always call to_f on the 
> end result.
>
> I might be Doing It Wrong, though. Maybe BigDecimal is the way to go?
>
>
>   
Another possibility is using a small, but >0, epsilon and check if the 
distance between the number and the limit is less than its value. Ruby 
does this automatically for you, if you use its #step functions:

 >> 98.3.step(98.6, 0.1).to_a
 # => [98.3, 98.4, 98.5, 98.6]
 >> 98.4.step(98.6, 0.1).to_a
 # => [98.4, 98.5, 98.6]

 >> (98.3..98.6).step(0.1).to_a
 # => [98.3, 98.4, 98.5, 98.6]
 >> (98.4..98.6).step(0.1).to_a
 # => [98.4, 98.5, 98.6]

Maybe the general advice here is, don't do it yourself, if Ruby offers a 
better way itself.

-- 
Florian Frank