Hi With the example, na.locf seems to be the easiest way. > library(zoo)
> na.locf(df1) ID ID_2 Firist Value 1 a aa TRUE 2 2 a ab FALSE 2 3 a ac FALSE 2 4 b aa TRUE 5 5 b ab FALSE 5 Cheers Petr > -----Original Message----- > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Jeff > Newmiller > Sent: Monday, January 8, 2018 9:13 AM > To: r-help@r-project.org; Ek Esawi <esaw...@gmail.com> > Subject: Re: [R] Replace NAs in split lists > > Upon closer examination I see that you are not using the split version of > df1 as I usually would, so here is a reproducible example: > > #---- > df1 <- read.table( text= > "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 > ", header=TRUE, as.is=TRUE ) > > sdf <- split( df1, df1$ID ) > # note the extra [ 1 ] in case you have more than one non-NA value # per ID > sdf2 <- lapply( sdf > , function( z ) { > z$Value <- ifelse( is.na( z$Value ) > , z$Value[ !is.na( z$Value ) ][ 1 ] > , z$Value > ) > z > } > ) > df2 <- do.call( rbind, sdf2 ) > df2 > #> ID ID_2 Firist Value > #> a.1 a aa TRUE 2 > #> a.2 a ab FALSE 2 > #> a.3 a ac FALSE 2 > #> b.4 b aa TRUE 5 > #> b.5 b ab FALSE 5 > > # or using tidyverse methods > > library(dplyr) > #> > #> Attaching package: 'dplyr' > #> The following objects are masked from 'package:stats': > #> > #> filter, lag > #> The following objects are masked from 'package:base': > #> > #> intersect, setdiff, setequal, union > df3 <- ( df1 > %>% group_by( ID ) > %>% do({ > mutate( . > , Value = ifelse( is.na( Value ) > , Value[ !is.na( Value ) ][ 1 ] > , Value > ) > ) > }) > %>% ungroup > ) > df3 > #> # A tibble: 5 x 4 > #> ID ID_2 Firist Value > #> <chr> <chr> <lgl> <int> > #> 1 a aa T 2 > #> 2 a ab F 2 > #> 3 a ac F 2 > #> 4 b aa T 5 > #> 5 b ab F 5 > #---- > > On Sun, 7 Jan 2018, Jeff Newmiller wrote: > > > 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. > > > > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... 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