[R] odd feature

[Gabor Grothendieck]

If you know that test is a scalar

result <- if (test) a else b

will do it.  Here is another approach:

as.vector(test * ts(a) + (!test) * ts(b))



On 5/21/06, ivo welch <ivowel at gmail.com> wrote:
> Dear R wizards:
>
> I just got stung by the ifelse() feature.
>
> > a <- 10:15
> > b <- 20:300
> > test <- 1
> > ifelse(test,a,b)
> [1] 10
>
> I had not realized that this was the default behavior---I had expected
> 10:15.  mea culpa.  however, I wonder whether it would make sense to
> replace ifelse with a different semantic, where if test is a single
> scalar, it means what a stupid user like me would imagine.
>
> Aside, I like the flexibility of R, but I am not thrilled by all the
> recycling rules.  I either mean I want a scalar or a vector of
> equal/appropriate dimension.  I never want a recycle of a smaller
> vector.  (I do often use a recycle of a scalar.)
>
> regards,
>
> /iaw
>
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