From: Heinz Tuechler <tuechler_at_gmx.at>

Date: Wed 10 Aug 2005 - 22:24:47 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Aug 10 22:29:28 2005

Date: Wed 10 Aug 2005 - 22:24:47 EST

Dear All,

where can I find information about how to write an assigment form of a
function?

For curiosity I tried to write a different form of the levels()-function,
since the original method for factor deletes all other attributes of a factor.
Of course, the simple method would be to use instead of levels(x) <-
newlevels, attr(x, 'levels') <- newlevels.

I tried the following:

## example

x <- factor(c(1,1,NA,2,3,4,4,4,1,2)); y <- x
attr(x, 'levels') <- c('a', 'b', 'c', 'd') # does what I want
x

[1] a a <NA> b c d d d a b
Levels: a b c d

'levels.simple<-' <- function (x, value) {

attr(x, 'levels') <- value

}

levels.simple(y) <- c('a', 'b', 'c', 'd') # does not what I want
y

[1] "a" "b" "c" "d"

Thanks,

Heinz Tüchler

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Aug 10 22:29:28 2005

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