From: Sammy Larbi <sam@...>
Date: 2007-09-21T21:04:46+09:00
Subject: Re: Idiomatic Ruby for Array#extract / Range#length?

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On 9/20/07, Sammy Larbi <sam@powersource.com> wrote:
>
> During the monthly meeting of our code dojo, we were surprised by a couple
> of things in Ruby, so I had a couple of questions I'd like to ask the
> community:
>
> 1) Would it make sense to talk about a Range having a length, as in:
>
> class Range
>       def length
>            self.end - self.begin
>       end
> end



There's been quite a lot of interesting discussion surrounding my first
question, which I truly appreciate and have enjoyed reading for the most
part.




2) What about a 2 dimensional slice (you want a submatrix, for example)?
>
> def test_extract_submatrix
>   assert_equal [[1,
> 2,3],[4,5,6
> ],[7,8,9]].extract_submatrix
> (1..2,1..2)
>  , [[5,6],[8,9
> ]]
> end
>
> class Array
>   def extract_submatrix(
> row_range, col_range)
>     self[row_range]
> .transpose[col_range].transpose
>   end
>
> end
>
>

But what about this 2-dimensional slice?  Any thoughts on that?  There is
already Array#transpose that assumes a 2D array, so I think it might fit.
Can you think of a better way to do it?



3)  Are the better/more idiomatic ways to do these?
>
> 4) Excuse my ignorance, as I've yet to use Facets, but are these the type
> of things it adds (and more)?  Are they already in there?
>
> Thanks and kind regards,
> Sam

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