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
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 <esawiek at 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
Hi library(zoo) has function na.locf, which probably can do what you want. so something like (untested) sdf1.fill<-lapply(sdf1, na.locf) do.call(rbind, sdf1.fill) Cheers. Petr> -----Original Message----- > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ek Esawi > Sent: Monday, January 8, 2018 4:36 AM > To: r-help at r-project.org > Subject: Re: [R] Replace NAs in split lists > > 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 <esawiek at 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 at 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.________________________________ Tento e-mail a jak?koliv k n?mu p?ipojen? dokumenty jsou d?v?rn? a jsou ur?eny pouze jeho adres?t?m. 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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 <esawiek at 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 <esawiek at 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 at 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.
Thank you all. Now everything works. Happy 2018 and beyond EK On Sun, Jan 7, 2018 at 10:13 PM, Ek Esawi <esawiek at 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