From: Benoit Daloze <eregontp@...>
Date: 2009-11-12T17:54:23+09:00
Subject: Re: Roman Numerals (Arrgh!)

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I didn't miss it at all, it's quite cool, but very not easy to find directly
and to explain for an homework ...

But I admit it's quite a nice solution, not that hard to understand.

2009/11/11 Gennady Bystritsky <Gennady.Bystritsky@quest.com>

>
> On Nov 11, 2009, at 11:59 AM, Benoit Daloze wrote:
>
> > Well, being student as well, I'd love to study Ruby instead of this
> (****)
> > Java. (Where are you studying?) But that's not the point.
> >
> > So, here is my piece of advice:
> >
> > Using $numerals = [
> >  [1000, "M"], [900, "CM"], [500, "D"], [400, "CD"],
> >  [100,  "C"], [90,  "XC"], [50,  "L"], [40,  "XL"],
> >  [10,   "X"], [9,   "IX"], [5,     "V"], [4,   "IV"],
> >  [1,    "I"]
> > ]
> >
> > ,you should iterate on each of them, seeing how much your number have of
> > this kind (/)
> > and what is the rest after that, to use it for the next step(%)...
> > (if you use Array#each, you'll get a new array(let's say a) like a=[dec,
> > romanString]. You can then take them separetely by a[0] and a[1].
> > Even if this method is not that beautiful in Ruby, it's the easiest way
> to
> > understand how to do it).
> >
> > That the way used in a very known book of Ruby.
> >
> > You just need to manage how to save this in your String at each step.
> > (You can multiply a String by "X" * 3, and concatenate using << (or +=))
> >
> > Give us your script when you'll got one working ;)
>
> In case you have missed it from yesterday, a slightly modified original
> solution was:
>
> def roman_numeral(number)
>  $numerals.inject(["", number]) { |(result, number), (order, roman)|
>    [ result + roman * (number / order), number % order ]
>  }.first
> end
>
> It works with shortened numerals for 4, 9, 40, 90, 400, 900 as well.
>
> Gennady.
>
>
>

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