[R] How to do it without for loops?

Gabor Grothendieck ggrothendieck at gmail.com
Tue Feb 28 14:43:15 CET 2006


Try:

crossprod(x)

or

t(x) %*% x

On 2/28/06, ronggui <ronggui.huang at gmail.com> wrote:
> This is the code:
>
> x<-matrix(rnorm(20),5)
> y<-list()
> for (i in seq(nrow(x))) y[[i]]<-t(x[i,,drop=F])%*%x[i,,drop=F]
> y[[1]]+y[[2]]+y[[3]]+y[[4]]+y[[5]]
>
> How can I do it without using for loops?
> Thank you in advance!
> --
> ronggui
> Deparment of Sociology
> Fudan University
>
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