sustraction of two vectors of matrix

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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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


?s 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]]