[Haskell-beginners] 2D rectanlge array type

[Nick Vanderweit]

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Hi Nathan,

It is actually possible (and pretty easy) to encode natural numbers as
types [1]. You could create a sequence type which is parameterized
over both the element type and the number of contained elements.


Nick

[1] http://www.haskell.org/haskellwiki/Type_arithmetic

On 09/12/2013 10:28 AM, Nathan Hüsken wrote:
> Hey,
> 
> I am experimenting with machine learning in haskell. For training
> a model, I need to input a list of features. A features itself is a
> set of floating point numbers. So my training data has the type:
> 
> [Feature]
> 
> What I am wondering is which type I should use for Feature. As I
> said, it is a set of floats. But every feature must have exactly
> the same number of floats. I could use
> 
> type Feature = [Float]
> 
> but that would not ensure that every feature has the same number
> of flaots. I could use tuples
> 
> type Feature = (Float,Float,Float,Float,Float ...)
> 
> The number of features varies from application to application. And
> I do not know how to encode that with tuples. Also the number of
> features can get very big (in extreme cases up to ~1000, in normal
> cases ~100).
> 
> How would you do that?
> 
> Thanks! Nathan
> 
> 
> _______________________________________________ Beginners mailing
> list Beginners at haskell.org 
> http://www.haskell.org/mailman/listinfo/beginners
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