[R] Replace NAs in split lists
Jeff Newmiller
jdnewmil at dcn.davis.ca.us
Mon Jan 8 16:45:26 CET 2018
"Enforce" is overstating it... results will differ if there are no non-NA values for a given ID, and there is a potential further discrepancy if there are multiple non-NA values. But these issues were not identified by the OP, so may not be relevant in their case.
--
Sent from my phone. Please excuse my brevity.
On January 8, 2018 6:41:33 AM PST, Eric Berger <ericjberger at gmail.com> wrote:
>You can enforce these assumptions by sorting on multiple columns, which
>leads to
>
>na.locf(df1[ order(df1$ID,df1$Value), ])
>
>
>
>On Mon, Jan 8, 2018 at 4:19 PM, Jeff Newmiller
><jdnewmil at dcn.davis.ca.us>
>wrote:
>
>> Yes, you are right if the IDs are always sequentially-adjacent and
>the
>> first non-NA value appears in the first record for each ID.
>> --
>> Sent from my phone. Please excuse my brevity.
>>
>> On January 8, 2018 2:29:40 AM PST, PIKAL Petr
><petr.pikal at precheza.cz>
>> wrote:
>> >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-bounces at r-project.org] On Behalf Of
>Jeff
>> >> Newmiller
>> >> Sent: Monday, January 8, 2018 9:13 AM
>> >> To: r-help at r-project.org; Ek Esawi <esawiek at 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 <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.
>> >> >
>> >> > ______________________________________________
>> >> > 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.
>> >> >
>> >>
>> >>
>> >-----------------------------------------------------------
>> ----------------
>> >> Jeff Newmiller The ..... .....
>Go
>> >Live...
>> >> DCN:<jdnewmil at dcn.davis.ca.us> Basics: ##.#. ##.#.
>Live
>> >Go...
>> >> Live: OO#.. Dead: OO#..
>> >Playing
>> >> Research Engineer (Solar/Batteries O.O#. #.O#.
>with
>> >> /Software/Embedded Controllers) .OO#. .OO#.
>> >rocks...1k
>> >>
>> >> ______________________________________________
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>> >http://www.R-project.org/posting-guide.html
>> >> and provide commented, minimal, self-contained, reproducible code.
>> >
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