Dear all,
I have a problem with the "subset()" function. I spent all day
yesterday
with a collegue to solve it and we did not find a satisfying
solution (even
in the archived mails), so I ask for your help.
Let's say (for a simple example) a matrix mat:
R> mat
cola colb colc
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
My goal is to select the lines of the matrix on the basis of the
values of
more than one column (let's say colb and colc).
For example I want to select all the lines of the matrix for which
values in
colb and colc are more than 4.
I tried several ways that did not work:
R> mat2 <- subset(mat, ("colb">4 & "colc">4))
R> mat2
[1] 1 2 3 4 5 6 7 8 9
it is a vector, not a matrix.
mat2 <- subset(mat, mat[,2:3]>4)
mat2
[1] 2 3 4 5 6 8 9
tha same: it is a vector; so I tried:
mat2 <- as.matrix(subset(mat, mat[,("colb">4 & "colc">4)]))
mat2
[,1]
[1,] 1
[2,] 2
[3,] 3
[4,] 4
[5,] 5
[6,] 6
[7,] 7
[8,] 8
[9,] 9
not good :(
Did someone have an idea of how to select the only the lines 2 and 3
of mat
by a selection on "colb" and "colc" >4 ?
Thanks a lot,
Florence.
Version 2.0.1 (2004-11-15)
(Linux Debian).
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