Hi:
And yet another: :)
library(plyr)
top2 <- function(x) {
y <- sort(x[-c(1, 2)], decreasing = TRUE)[1:2]
area <- rep(x[1], 2)
type <- rep(x[2], 2)
data.frame(area, type, value = y, variable = names(y))
}
v <- ldply(apply(df, 1, top2), rbind)
The last line does the list creation and do.call() steps together.
HTH,
Dennis
On Thu, Feb 10, 2011 at 4:38 PM, jim holtman <jholt...@gmail.com> wrote:
> here is another way of doing it:
>
> > set.seed(19)
> >
> > area<-c(rep(1,10),rep(2,10),rep(3,10),rep(4,10),rep(5,10))
> > type<-c(rep(1:10,5))
> > a<-rnorm(50)
> > b<-rnorm(50)
> > c<-rnorm(50)
> > d<-rnorm(50)
> > df<-cbind(area,type,a,b,c,d)
> > df1 <- data.frame(df)
> > require(reshape2)
> > df.melt <- melt(df1, id=c('area', 'type'))
> > result <- do.call(rbind,
> + lapply(split(df.melt, list(df.melt$area, df.melt$type),
> drop=TRUE), function(x){
> + head(x[order(x$value, decreasing=TRUE),], 2) # get at most
> the first two if present
> + })
> + )
> >
> > result
> area type variable value
> 1.1.51 1 1 b 1.70366970
> 1.1.101 1 1 c 0.79101298
> 2.1.161 2 1 d 1.56797593
> 2.1.61 2 1 b 0.79868725
> 3.1.21 3 1 a 1.42342348
> 3.1.121 3 1 c 0.44547975
> 4.1.131 4 1 c 1.72745545
> 4.1.31 4 1 a 1.50474144
> 5.1.141 5 1 c 1.72521942
> 5.1.191 5 1 d 0.52466470
>
>
> On Thu, Feb 10, 2011 at 12:55 PM, Phil Spector
> <spec...@stat.berkeley.edu> wrote:
> > Alain -
> > Here's a reproducible data set:
> >
> > set.seed(19)
> > area<-c(rep(1,10),rep(2,10),rep(3,10),rep(4,10),rep(5,10))
> > type<-c(rep(1:10,5))
> > a<-rnorm(50)
> > b<-rnorm(50)
> > c<-rnorm(50)
> > d<-rnorm(50)
> > df<-cbind(area,type,a,b,c,d)
> >
> > First I'll make a helper function to operate on one row of the data
> frame:
> >
> > get2 = function(x){
> > y = x[-c(1,2)]
> > oy = order(y,decreasing=TRUE)
> > nms = colnames(df)[-c(1,2)]
> > data.frame(area=rep(x[1],2),type=rep(x[2],2),
> > max=y[oy[1:2]],colname=nms[oy[1:2]])
> > }
> >
> > Now I can use apply, do.call and rbind to get the answer:
> >
> >> answer = do.call(rbind,apply(df,1,get2))
> >> head(answer)
> >
> > area type max colname
> > b 1 1 1.7036697 b
> > c 1 1 0.7910130 c
> > c1 1 2 2.4576579 c
> > a 1 2 0.3885812 a
> > c2 1 3 1.2363598 c
> > a1 1 3 -0.3443333 a
> >
> > (My numbers differ from yours because you didn't specify
> > a seed for the random number generator)
> >
> > I'm not exactly sure how to form your column "combination", though.
> >
> > - Phil Spector
> > Statistical Computing Facility
> > Department of Statistics
> > UC Berkeley
> > spec...@stat.berkeley.edu
> >
> >
> > On Thu, 10 Feb 2011, Alain D. wrote:
> >
> >> Dear R-List,
> >>
> >> I have a dataframe
> >>
> >> area<-c(rep(1,10),rep(2,10),rep(3,10),rep(4,10),rep(5,10))
> >> type<-c(rep(1:10,5))
> >> a<-rnorm(50)
> >> b<-rnorm(50)
> >> c<-rnorm(50)
> >> d<-rnorm(50)
> >> df<-cbind(area,type,a,b,c,d)
> >>
> >>
> >> df
> >> area type a b
> >> c d
> >> [1,] 1 1 0.45608192 0.240378547 2.05208079 -1.18827462
> >> [2,] 1 2 -0.12119506 -0.028078577 -2.64323695 -0.83923441
> >> [3,] 1 3 0.09066133 -1.134069619 1.53344812 -0.15670239
> >> [4,] 1 4 -1.34505241 1.919941172 -1.02090099 0.75664358
> >> [5,] 1 5 -0.29279617 -0.314955019 -0.88809266 2.22282022
> >> [6,] 1 6 -0.59697893 -0.652937746 1.05132400 -0.02469151
> >> [7,] 1 7 -1.18199400 0.728165962 -1.51419348 0.65640976
> >> [8,] 1 8 -0.72925659 0.303514237 0.79758488 0.93444350
> >> [9,] 1 9 -1.60080508 -0.187562633 0.51288428 -0.55692877
> >> [10,] 1 10 0.54373268 -0.494994392 0.52902381 1.12938122
> >> [11,] 2 1 -1.29675664 -0.644990784 -2.44067511 -0.18489544
> >> [12,] 2 2 0.86330699 1.458038882 1.17514710 1.32896878
> >> [13,] 2 3 0.30069402 1.361211939 0.84757211 1.14502761
> >> ...
> >>
> >> Now I want to have for each combination of area and type the name and
> >> corresponding value of the two columns with the highest and second
> highest
> >> value a,b,c,d.
> >> In the above example it should be something like
> >>
> >> combination max colname
> >> 11 2.05 c
> >> 11 0.46 a
> >> 12 -0.03 b
> >> 12 -0.12 a
> >> ...
> >>
> >> (It might be arranged differently, though)
> >>
> >> Can anyone help?
> >>
> >> Thank you in advance!
> >>
> >> Alain
> >>
> >> [[alternative HTML version deleted]]
> >>
> >> ______________________________________________
> >> R-help@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.
> >>
> >
> > ______________________________________________
> > R-help@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.
> >
>
>
>
> --
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
>
> ______________________________________________
> R-help@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.
>
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and provide commented, minimal, self-contained, reproducible code.
