On Nov 27, 2009, at 5:34 AM, Vitória Magalhães Piai wrote:
Hi,
I'm quite new using R and have got no one to help me get through it.
Hopefully someone can help me with one problem I've been struggling
with for the last hours!!
(Sorry if I'm using the wrong terminology as well!)
I have a data matrix in which SIE is one of my variables. What I
need to do now is to create a new variable (group) if a certain
condition in SIE is met.
I tried:
if (data2$SIE < 50.646){
data2$group=as.factor("small")
}
which gives me "In if (data2$SIE < 50.646) { : the condition has
length > 1 and only the first element will be used"
If ( cond) is not vectorised. Ifelse is.
and
ifelse (data2$SIE < 50.64593, data2$group =
as.factor("small"),data2$group = as.factor("large"))
with "Error: unexpected '=' in "ifelse (data2$SIE < 50.64593,
data2$group ="
Almost... try:
data2$group <- ifelse (data2$SIE < 50.64593, as.factor("small"),
as.factor("large") )
... but that looks wrong to my wetware R interpreter, too, so could
also try:
data2$group <- factor( ifelse (data2$SIE < 50.64593, "small", "large" )
(And of course this would have been tested had you supplied a small
test dataset, but this week I am being passive aggressive toward
persons who don't follow the Posting Guide.)
--
David
I tried all other kinds of variations and so far, nothing!!
Is there a good way to do this that someone could teach me?
Thank you so much,
Vitória
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
