On 27/10/2009, at 4:26 PM, jmark17 wrote:
I am sure this question has come up, but searching hasn't given me any
results.
So I need to enter this line:
mx1 <- randomForest(X1 ~ elevation + slope + vegtype, data =
moths.train)
But the problem is that X1 is currently hard coded. I would instead
like to
be able to put in the value of X1 through a list. For example:
list <- list("X1", "X2", "X3")
#Then, instead of X1, I want to put list[1]
No you don't. You *might* want to put list[[1]] --- learn
the difference between [[]] and [] for lists, i.e. RTFM, in
particular ?"[" --- but it still wouldn't work.
mx1 <- randomForest(list[1] ~ elevation + slope + vegtype, data =
moths.train)
randomForest does not accept list[1] as a valid entry, so how can I
get it
to accept it as X1, instead of list[1]?
(a) Don't call your list ``list''. (Cf. fortune("dog").)
(b) You really want a character *vector* not a list. E.g.
nms <- c("X1", "X2", "X3")
(c) Execute
fmla <- as.formula(paste(nms[1],"~ elevation + slope + vegtype"))
mxl <- randomForest(fmla,data=moths.train)
Have tested the construction of ``fmla'' --- that works. I don't know
from randomForest(), so I haven't tested that bit.
HTH.
cheers,
Rolf Turner
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