[R] data.frame transformation

[Christian Hof]

Dear all,
maybe somebody can provide some help for this problem:

Example:
I've got the following dataframe "data":

grid.id<-c(1:4)
lat<-c(10,12,13,15)
species1<-c(0,0,0,1)
species2<-c(1,1,0,0)
species3<-c(1,1,1,1)
data<-data.frame(cbind(grid.id,lat,species1,species2,species3))

How can I, out of "data" make a new dataframe, where the cells of value 
"1" in the species columns ("species1" to "species3") are replaced by 
the respective "lat" values automatically - so that the final dataframe 
looks like this:

specieslat1<-c(0,0,0,15)
specieslat2<-c(10,12,0,0)
specieslat3<-c(10,12,13,15)
data.frame(cbind(grid.id,lat,specieslat1,specieslat2,specieslat3))

?

Thanks a lot,
cheers
Christian

-- 
                        Christian Hof .. PhD student
     Biodiversity & Global Change Lab .. C/José Gutiérrez Abascal, 2
Museo Nacional de Ciencias Naturales .. E-28006 Madrid (España)
                                         www.biochange-lab.eu
              Center for Macroecology .. University of Copenhagen
                                         www.macroecology.ku.dk
                            mobile ES .. +34 697 508 519
                            mobile DE .. +49 176 205 189 27
                                 mail .. chof at bi.ku.dk
                                 blog .. www.vogelwart.de