> From: Barry Rowlingson
>
> Liaw, Andy wrote:
> > If you insist, here's one way:
> >
> > my.blockwisesum <- function(x, n, ...) {
> > tapply(x, seq(1, length(x), by=n), sum, ...)
> > }
> >
>
> Did you test that? I get:
Of course not (slap on wrist)!! My apologies...
Andy
> > my.blockwisesum(1:10, 3)
> Error in tapply(x, seq(1, length(x), by = n), sum, ...) :
> arguments must have same length
>
>
> Here's my solution with tapply and rep() to generate a vector like
> c(1,1,1,2,2,2,3,3,3,4):
>
> baz.blockwisesum=
>
> function(v,n){tapply(v,rep(1:(1+length(v)/n),each=n)[1:length(
> v)],sum)}
>
> > baz.blockwisesum(1:10,3)
> 1 2 3 4
> 6 15 24 10
>
> - just ignore the 1 to 4 names, they cant hurt you.
>
> Baz
>
>
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