From: "S. Robert James" <srobertjames@...>
Date: 2007-02-24T06:25:06+09:00
Subject: Re: enum_cons with tail

I'm not sure how to do either of those.  Like I said, this is a File,
not a true Array.  (The magic of Ruby makes it Enumerable, but I
haven't mastered that magic yet.)

On Feb 23, 3:54 pm, "Kenosis" <keno...@gmail.com> wrote:
> On Feb 23, 11:50 am, "S. Robert James" <srobertja...@gmail.com> wrote:
>
>
>
> > enum_cons chops off the tail of the collection, if it isn't evenly
> > divisble:
>
> > e.g.:
> >     (1..10).each_cons(3) {|a| p a}
> >     # outputs below
> >     [1, 2, 3]
> >     [2, 3, 4]
> >     [3, 4, 5]
> >     [4, 5, 6]
> >     [5, 6, 7]
> >     [6, 7, 8]
> >     [7, 8, 9]
> >     [8, 9, 10]
>
> > I'd also like to get:
> > [9, 10, nil]
> > [10, nil, nil]
>
> > Is there anyway to do this?  (The collection is an opened File, too
> > large to load entirely in memory.)
>
> > I don't have a clear grasp as to how internally Ruby treats a File as
> > Enumerable.
>
> Not that I am aware of.  Two things come to mind.  1) You could append
> nil items to your array to make it evenly divisable, 2) you could
> extend arrary with your own each_cons that does what you want.  Hope
> this is at least some help.  Perhaps others will know a more direct
> way to accomplish what you seek.
>
> Ken