From: Chad Perrin <code@...>
Date: 2011-03-30T05:08:36+09:00
Subject: Re: Why can a floating point number be used as an array index?

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On Wed, Mar 30, 2011 at 03:35:21AM +0900, Jeff Dik wrote:
> Why can a floating point number be used as an array index?  Anybody
> know of a good use case for this?
>=20
> irb(main):020:0> [1, 2, 3][0.3]
> 1
> irb(main):021:0> [1, 2, 3][0.9]
> 1

I don't know about why, exactly, or about use cases (though I suppose it
might just make things easier sometimes, without errors cropping up all
over the place if you're working with floating point numbers a lot and
are too lazy to do integer conversions yourself).  How seems, from a
little experimenting, to be self-evident to me:

    $ irb
    irb(main):001:0> [1,2,3][0.7]
    =3D> 1
    irb(main):002:0> [1,2,3][1.7]
    =3D> 2
    irb(main):003:0> [1,2,3][1.1]
    =3D> 2
    irb(main):004:0> [1,2,3][-0.1]
    =3D> 1
    irb(main):005:0> [1,2,3][-1.1]
    =3D> 3

It looks like it just does integer truncation.

--=20
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]

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