[R] data.frame
Chong Gu
chong at stat.purdue.edu
Mon Jun 7 23:55:15 CEST 1999
I am not sure if I should call this a bug or just a design
imperfection.
I have noticed that the data.frame function does not preserve the
integrity of multivariate components. Here is a simple illustration:
> x <- matrix(1:6,3,2)
> y <- 1:3
> z <- data.frame(x=x,y=y)
> z$x
# NULL
> z$y
# [1] 1 2 3
One can however get by that by using model.frame:
> zz <- model.frame(~x+y)
> zz$x
# [,1] [,2]
# [1,] 1 4
# [2,] 2 5
# [3,] 3 6
I was expecting data.frame to behave like this.
I am developing some multivariate nonparametric modeling tools using
smoothing splines, with syntax similar to lm and glm. In a formula
say y~x1*x2, x1 or x2 or both can be multivariate. The corresponding
predict function also has syntax similar to that of lm. To prepare
newdata to be used in predict(object,newdata,...), I can use
> newdata <- data.frame(x1=newx1,x2=newx2)
only for univariate x1 and x2. For multivariate predictors, I have to
fake it by using
> newdata <- model.frame(~x1+x2,list(x1=newx1,x2=newx2))
Chong Gu
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
More information about the R-help
mailing list