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.
> > >
> >
>
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