On Jun 20, 2011, at 3:54 PM, Costis Ghionnis wrote:
Hallo everyone! I have a problem about creating a matrix...
Suppose we have a vector y<-c(1,1,1,3,2)
and a zero matrix, m ,with nrows=length(y) and ncol=4.
The matrix would look like this:
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
I want to change the first three rows with the vector c(1,2,3,4).
I thought that with the command m[y==1,1:4]<-c(1,2,3,4) i would get
1 2 3 4
1 2 3 4
1 2 3 4
0 0 0 0
0 0 0 0
Try:
> m[y==1,1:4]<-rep( c(1,2,3,4), each= sum(y==1) )
> m
[,1] [,2] [,3] [,4]
[1,] 1 2 3 4
[2,] 1 2 3 4
[3,] 1 2 3 4
[4,] 0 0 0 0
[5,] 0 0 0 0
--
David.
but instead i am getting
1 4 3 2
2 1 4 3
3 2 1 4
0 0 0 0
0 0 0 0
It seems it is filling the data by col instead by row. I want to use
this technique in more complicated problems.
So i do not want to have to work with the transpose matrix. Do you
know another way to make this work. Thank you...
______________________________________________
R-help@r-project.org mailing list
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.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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.
