or with no loops and no preallocation:
bb <- aa[ , 2:5 ] - aa[ , 1:4 ]
On December 5, 2018 8:51:16 AM PST, Rui Barradas <ruipbarra...@sapo.pt> wrote:
>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,
>
>Rui Barradas
>
>
>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@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>______________________________________________
>R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
--
Sent from my phone. Please excuse my brevity.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
