That fails: The manual says:
tapply(X, INDEX, FUN = NULL, ..., simplify = TRUE) ArgumentsXan atomic object, typically a vector.INDEXlist of factors, each of same length as X. The elements are coerced to factors by as.factor<http://127.0.0.1:31214/library/base/help/as.factor> . my error says: Error in tapply(DF[, 1:15], DF$Year, mean, na.rm = T) : arguments must have same length The issue that I have is I dont understand what the requirements for the list of factors are. In my example DF$Years is a sequence of years..1979,1980,1982,1983, 1987.. like that with missing years: so when the manual say: list of factors each the same length as X? what does that mean? I could have a DF with 20 rows and only two different years. or 20 rows and 20 different years. Suppose: a<- c(1,2,3,4) > b<-c(2,3,4,5) > df=data.frame(a,b) > length(df) The length of DF is 2. Does that mean the "list of factors, each of same length as X." would have to be 2? that doesnt seem to make sense. On Mon, Apr 26, 2010 at 12:26 AM, Petr PIKAL <petr.pi...@precheza.cz> wrote: > Hi > > r-help-boun...@r-project.org napsal dne 26.04.2010 06:52:55: > > > Having some difficulties with understanding how tapply works and getting > > return values I expect > > > > Data: dataframe. DF DF$Id $D $Year....... > > > > Id D Year Jan Feb Mar Apr May Jun Jul Aug Sep > Oct > > Nov Dec > > 11264402000 1 1980 NA NA NA NA NA 212 203 209 228 237 NA > NA > > 11264402000 0 1981 NA NA 243 244 NA NA NA NA 225 NA 231 > NA > > 11264402000 1 1981 NA 251 NA 248 241 NA NA NA 235 NA NA > 245 > > 11264402000 0 1982 236 237 242 240 242 205 199 NA NA NA NA > NA > > 11264402000 1 1982 236 NA NA 240 242 NA NA NA NA NA NA > NA > > 11264402000 0 1983 NA 247 NA NA NA NA NA 205 NA NA NA > NA > > 11264402000 1 1983 NA 247 NA NA NA NA NA NA NA 225 NA > NA > > 11264402000 0 1986 NA NA NA 240 NA NA NA 213 NA NA NA > NA > > 11264402000 0 1987 241 NA NA NA NA 218 NA NA 235 243 240 > NA > > 11264402000 1 1987 NA NA NA NA NA 218 NA NA 235 243 240 > NA > > 11264402000 3 1987 NA NA NA NA NA 218 NA NA 235 243 240 > NA > > 11264402000 0 1988 238 246 249 NA 244 213 212 224 232 238 232 > 230 > > 11264402000 1 1988 238 246 249 246 244 213 212 224 232 NA NA > 230 > > 11264402000 3 1988 238 246 249 246 244 213 212 224 232 NA NA > 230 > > 11264402000 0 1989 232 233 238 239 231 NA 215 NA NA NA NA > 238 > > 11264402000 1 1989 232 233 238 239 231 NA NA NA NA NA NA > 238 > > 11264402000 3 1989 232 233 238 239 231 NA NA NA NA NA NA > 238 > > > > and the result should be a dataframe of column means by year with the > > variable D dropped (or kept doesnt matter) > > > > 11264402000 1 1980 NA NA NA NA NA 212 203 209 228 237 NA > NA > > 11264402000 .5 1981 NA NA 243 244 NA NA NA NA 225 NA 231 > NA > > 11264402000 .5 1982 236 237 242 240 242 205 199 NA NA NA NA > NA > > 11264402000 .5 1983 NA 247 NA NA NA NA NA 205 NA 225 NA > > NA > > 11264402000 1 1986 NA NA NA 240 NA NA NA 213 NA NA NA > NA > > 11264402000 2 1987 241 NA NA NA NA 218 NA NA 235 243 240 > NA > > 11264402000 1.33 1988 238 246 249 246 244 213 212 224 232 238 > 232 > > 230 > > 11264402000 1.33 1989 232 233 238 239 231 NA 215 NA NA NA > NA > > 238 > > > > It would seem that Tapply should work > > result<-tapply( DF[,1:15], DF$Year, colMeans,na.rm=T) > > Why colMeans? It is function used instead of apply(...,.. ,mean). > > Maybe you want > > result<-tapply( DF[,1:15], DF$Year, mean,na.rm=T) > > Regards > Petr > > > > > but i get errors about the length of arguments, which > > > > [[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. > > [[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.
