# [R] sustraction of two vectors of matrix

Rui Barradas ruipb@rr@d@@ @ending from @@po@pt
Wed Dec 5 17:51:16 CET 2018

```Hello,

1) You don't need matrix(outer(etc)), outer already returns a matrix.
2) You need to create bb first.

aa <- outer(0:3, 0:4, function(x,y) x + y*2)

bb <- matrix(nrow = 4, ncol = 4)

for(i in 1:4){
for(j in 2:5){
bb[i, j - 1] <- aa[i, j] - aa[i, j - 1]
}
}

bb

Hope this helps,

Às 14:30 de 05/12/2018, malika yassa via R-help escreveu:
> helloplease   I want to make a sustration of two vectors of a matrix
> i have this program
>
> aa<-matrix(outer(0:3,0:4,function(x,y) x+y*2),nrow=4,ncol=5)
> for(i in 1:4)
> + {for(j in 2:5)
> + {bb[i,j-1]=aa[i,j]-aa[i,j-1]
> + }
> + }
> at the end i obtain the bb=matrix( nrow=4,ncol=4)
> but i cann't obtain this matrix
> thank you very much
>
>
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help