Why do you want to modify df1? Why not just reassemble the parts as a new data frame and use that going forward in your calculations? That is generally the preferred approach in R so you can re-do your calculations easily if you find a mistake later. -- Sent from my phone. Please excuse my brevity.
On January 7, 2018 7:35:59 PM PST, Ek Esawi <esaw...@gmail.com> wrote: >I just came up with a solution right after i posted the question, but >i figured there must be a better and shorter one.than my solution >sdf1[[1]][1,4]<-lapplyresults[[1]] >sdf1[[2]][1,4]<-lapplyresults[[2]] > >EK > >On Sun, Jan 7, 2018 at 10:13 PM, Ek Esawi <esaw...@gmail.com> wrote: >> Hi all-- >> >> I stumbled on this problem online. I did not like the solution given >> there which was a long UDF. I thought why cannot split and l/s apply >> work here. My aim is to split the data frame, use l/sapply, make >> changes on the split lists and combine the split lists to new data >> frame with the desired changes/output. >> >> The data frame shown below has a column named ID which has 2 >variables >> a and b; i want to replace the NAs on the Value column by 2, which is >> the only numeric entry, for ID=a and by 5 for ID=b. >> >> I worked out the solution but could not replace the results in the >split lists. >> >> Original dataframe , df1 >> ID ID_2 Firist Value >> 1 a aa TRUE 2 >> 2 a ab FALSE NA >> 3 a ac FALSE NA >> 4 b aa TRUE 5 >> 5 b ab FALSE NA >> Sdf1 >> $a >> ID ID_2 Firist Value >> 1 a aa TRUE 2 >> 2 a ab FALSE NA >> 3 a ac FALSE NA >> $b >> ID ID_2 Firist Value >> 4 b aa TRUE 5 >> 5 b ab FALSE NA >> Desired results >> ID ID_2 Firist Value >> 1 a aa TRUE 2 >> 2 a ab FALSE 2 >> 3 a ac FALSE 2 >> >> $b >> ID ID_2 Firist Value >> 4 b aa TRUE 5 >> 5 b ab FALSE 5 >> >> My code >> >> sdf <- split(df1,df$ID) >> lapply(sdf, function(z) >ifelse(is.na(z$Value),z$Value[!is.na(z$Value)],z$Value)) >> result: >> $ a: num [1:3] 2 2 2 >> $ b: num [1:2] 5 5 >> >> How could I put these two lists back in the split data frame, sdf1? >> Then I could use do.call to reassemble a data frame from the split >> lists, >> >> Thanks, >> EK > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >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 -- To UNSUBSCRIBE and more, see 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.
