[R] sustraction of two vectors of matrix

[Rui Barradas]

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

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
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[Jeff Newmiller]

or with no loops and no preallocation:

bb <- aa[ , 2:5 ] - aa[ , 1:4 ]

Post by Rui Barradas
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

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]]
______________________________________________
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.

______________________________________________
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.