?cut This would recode to a factor with numeric labels for its levels. as.numeric(as.character(...))would then convert the labels to numeric values that you can manipulate. This presumes that the variable you are coding is numeric and you want to recode by binning the values into ordered bins.
Bert Gunter Genentech Nonclinical Statistics -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Lauri Nikkinen Sent: Friday, May 18, 2007 8:02 AM To: Gabor Grothendieck Cc: [email protected] Subject: Re: [R] Simple programming question Thank you all for your answers. Actually Gabor's first post was right in that sense that I wanted to have "low" to all cases which are lower than second highest. But how about if I want to convert/recode those "high", "mid" and "low" to numeric to make some calculations, e.g. 3, 1, 0 respectively. How do I have to modify your solutions? I would also like to apply this solution to many kinds of recoding situations. -Lauri 2007/5/18, Gabor Grothendieck <[EMAIL PROTECTED]>: > > There was a problem in the first line in the case that the highest number > is not unique within a category. In this example its not apparent since > that never occurs. At any rate, it should be: > > f <- function(x) 4 - pmin(3, match(x, sort(unique(x), decreasing = TRUE))) > factor(ave(dfr$var3, dfr$categ, FUN = f), lab = c("low", "mid", "high")) > > Also note that the factor labels were arranged so that > "low", "mid" and "high" correspond to levels 1, 2 and 3 > respectively. > > On 5/18/07, Gabor Grothendieck <[EMAIL PROTECTED]> wrote: > > Try this. f assigns 1, 2 and 3 to the highest, second highest and third > highest > > within a category. ave applies f to each category. Finally we convert > it to a > > factor. > > > > f <- function(x) 4 - pmin(3, match(x, sort(x, decreasing = TRUE))) > > factor(ave(dfr$var3, dfr$categ, FUN = f), lab = c("low", "mid", "high")) > > > > > > > > On 5/18/07, Lauri Nikkinen <[EMAIL PROTECTED]> wrote: > > > Hi R-users, > > > > > > I have a simple question for R heavy users. If I have a data frame > like this > > > > > > > > > dfr <- data.frame(id=1:16, categ=rep(LETTERS[1:4], 4), > > > var3=c(8,7,6,6,5,4,5,4,3,4,3,2,3,2,1,1)) > > > dfr <- dfr[order(dfr$categ),] > > > > > > and I want to score values or points in variable named "var3" > following this > > > kind of logic: > > > > > > 1. the highest value of var3 within category (variable named "categ") > -> > > > "high" > > > 2. the second highest value -> "mid" > > > 3. lowest value -> "low" > > > > > > This would be the output of this reasoning: > > > > > > dfr$score <- > > > > factor(c("high","mid","low","low","high","mid","mid","low","high","mid","low ","low","high","mid","low","low")) > > > dfr > > > > > > The question is how I do this programmatically in R (i.e. if I have > 2000 > > > rows in my dfr)? > > > > > > I appreciate your help! > > > > > > Cheers, > > > Lauri > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > [email protected] mailing list > > > https://stat.ethz.ch/mailman/listinfo/r-help > > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > > and provide commented, minimal, self-contained, reproducible code. > > > > > > [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
