You need to review:
?update
?update.formula
?as.formula
The way should be clear at that point. If not, then include a
reproducible data example to work with.
--
David
On Nov 15, 2009, at 9:23 AM, Karsten Weinert wrote:
Hello,
at the Rgui command line I can easily remove a term from a fitted lm
object, like
fit <- lm(y~x1+x2+x3, data=myData)
update(fit, .~.-x1)
However, I would like to do this in a function with term given as
string, like
removeTerm <- function(linModel, termName) { ??? }
removeTerm(fit, "x1")
but I can not fill the ???. I already tried
removeTerm <- function(linModel, termName) { update(linModel, .~. -
termName },
removeTerm <- function(linModel, termName) { update(linModel, .~. -
as.name(termName) },
removeTerm <- function(linModel, termName) { update(linModel, .~. -
eval(termName) },
removeTerm <- function(linModel, termName) { update(linModel, .~. -
eval.parent(termName) },
removeTerm <- function(linModel, termName) { update(linModel, .~. -
get(termName) },
but these attempts produce error messages.
Can you advise me here?
Kind regards,
Karsten
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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