On 2011-06-27 03:02, 新鼎-智慧製造事業處-鄭紹文 wrote:
Dear sir,
If I have a vector as:
y<- c(1:4)
and a matrix as:
x<- matrix (5:12, nrow=4, ncol=2)
Then I create a data frame as:
t<- data.frame(y, x)
R will generate a data frame of 3 columns
names(t)
"y" "X1" "X2"
is.vector(t$X1) returns TRUE
is.vector(t$X2) returns TRUE
R splits the columns of a matrix into column vectors automatically.
How should I create a data frame of t$y& t$x such that
is.vector(t$y) returns TRUE
is.matrix(t$x) returns TRUE
That is, how to make x column of the data frame a matrix? Just like the test
data ¡§gasoline¡¨ in your PLS package:
library(pls)
data(yarn)
is.vector(density) returns TRUE
is.matrix(NIR) returns TURE (NIR is a matrix)
This is all perfectly well described in ?data.frame where
you will also find reference to the use of I() to
accomplish your goal.
Peter Ehlers
Best regards,
Shaowen Cheng
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