[R-sig-Geo] Help to count in apply(...)

[Robert Hijmans]

Dear Gianni,

I think you want this:

tapply(areaFe$K <= fer.conc.max, areaFe$ID, sum, na.rm=TRUE)

E.g.:

ID <- rep(1:10, each=10)
K <- runif(100)
areaFe <- as.data.frame(cbind(ID, K))
fer.conc.max <- 0.5
tapply(areaFe$K <= fer.conc.max, areaFe$ID, sum, na.rm=TRUE)


Robert


On Fri, Mar 13, 2009 at 9:58 AM, gianni lavaredo
<gianni.lavaredo at gmail.com> wrote:
> dear User
>
> I'm quite new to R and trying to learn the basic and sorry for the email. I
> don't wish abuse of mail-list. I had read manual and Help online about
> tapply (...). I have a data frame and I need "count" the Fe value with sum
> for every ID sample area
>
> fer.conc.max <- tapply(areaFe$K, areaFe$ID, max, na.rm=TRUE)
>
> I need to count the Fe area with Fe$K <=  fer.conc.max
>
> # give me the summatory and not the count
> fer.conc.max <- tapply(areaFe$K, areaFe$ID, sum, na.rm=TRUE)
>
> I tried sever combination that I found in mail-list archive but alway I have
> a error message
>
> thanks Gianni
>
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