[R] function similar to ddply? + calculations based on previous row
R. Michael Weylandt
michael.weylandt at gmail.com
Thu Feb 16 03:38:54 CET 2012
Hi,
I got a little lost in your verbal description, but if I understand
your code correctly (what is n?), I think I'd implement it with the
split function: step i) make a single (hopefully vectorized) pass to
get whatever split points you need (the offset is in this step); ii)
use split() to break your data.frame into a list efficiently; iii) use
lapply() to run your function on each element of the list.
Hope that helps,
Michael
On Wed, Feb 15, 2012 at 4:25 PM, Nerak <nerak.t at hotmail.com> wrote:
> I saw I made a little mistake in the loop,
> in the line
> test.number$numberb[y-Year[1]+1]<-length(which(test.starty==1 &
> test.f[(n+1)]== 1 ))
> it is n+1 instead of n-1 (like I wrote in the beginning)
>
> But the question I have about it is still the same.
> My excuzes
>
>
>
> Year<-data.frame(Date=c(1980,1980,1980,1980,1981,1981,1981,1981,1982,1982,1982,1982,1983,1983,1983,1983))
> test.b<-data.frame(C=c(0,0,0,0,5,2,0,0,0,15,12,10,6,0,0,0),B=c(0,0,0,0,9,6,2,0,0,24,20,16,2,0,0,0),F=c(0,0,0,0,6,5,1,0,0,18,16,12,10,5,1,0))
> test.start<-data.frame(C=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0),B=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0),F=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0))
>
>
>
> test.2b<-test.b>1
> test.number<-data.frame(c(1980:1983))
> for (l in 1:nrow(test.b))
> {
> for (y in 1980:1983)
> {
>
> test.f<-test.2b[which(Year == y),l]
> test.starty<-test.start[which(Year ==y),l]
> test.number$numberb[y-Year[1]+1]<-length(which(test.starty==1 &
> test.f[(n+1)]== 1 ))
>
> }
> test.number[,l+1]<-cbind(test.number$numberb)
>
> }
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/function-similar-to-ddply-calculations-based-on-previous-row-tp4390925p4392040.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org 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.
More information about the R-help
mailing list