I guess I wasn't very clear. The goal is not to define diff on a different
object type, but to have a different 'subtraction' operator with the same
lag logic. An easy example would be quotient instead of subtraction. Of
course I could do that by simply cutting and pasting diff.default and
replacing '-'(a,b) with f(a,b), but it's cleaner to use a standard function
if there is one.
-s
On Mon, May 18, 2009 at 5:05 PM, Gabor Grothendieck <ggrothendi...@gmail.com
> wrote:
> You can define a new class for the object diff operates
> on and then define your own diff method for that. For
> some examples see:
>
> methods(diff)
>
>
>
> On Mon, May 18, 2009 at 4:24 PM, Stavros Macrakis <macra...@alum.mit.edu>
> wrote:
> > I would like to apply a function 'f' to the lagged version of a vector
> and
> > the vector itself.
> >
> > This is easy to do explicitly:
> >
> > mapply( f, v[-1], v[-length(v)] )
> >
> > or in the case of a pointwise vector function, simply
> >
> > f( v[-1], v[-length(v)] )
> >
> > This is essentially the same as 'diff' but with an arbitrary function,
> not
> > '-'.
> >
> > Is there a standard way to do this? Is there any particular reason that
> > 'diff' should not have an 'f' argument?
> >
> > -s
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> > PLEASE do read the posting guide
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> > and provide commented, minimal, self-contained, reproducible code.
> >
>
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