# [R] (almost) rolling function or fill?

Bert Gunter bgunter@4567 @end|ng |rom gm@||@com
Mon Jun 8 23:00:42 CEST 2020

```This is a plain text list. Your html post was completely mangled. Re-post

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Mon, Jun 8, 2020 at 1:08 PM Andras Farkas via R-help <
r-help using r-project.org> wrote:

> Hello,
> please see if you have a thought on how to achieve the following:
> we have:
>  df<-data.frame(a=Sys.Date()+1:10,
>  b=Sys.Date()+c(NA,NA,NA,rep(3,4),NA,NA,3),
>  c=Sys.Date()+c(NA,NA,NA,rep(9,4),NA,NA,9))
>
>
> the idea I have difficulty wrapping my head around is to do the following:
> I need the system to look at df\$a by row (lets call it the index row) and
> look at df\$b and df\$c 1 row before the given row in df\$a  (lets call it
> index row -1) and evaluate if the index row value in df\$a falls into the
> range (>= and <=) of the index row -1 values in df\$b and df\$c. If it does,
> then copy over the index row -1 values in df\$b and df\$c into the index row
> in df\$b and df\$c, if not place an NA in both cells of the index row in df\$b
> and df\$c.
>  examples:
> 1. the date value in df\$a is between df\$b and df\$c so we can copy
> the values in df\$b and df\$c into df\$b and df\$c2.  the date
> value in df\$a is between df\$b and df\$c (as we copied it in in step
> 1)  so we can copy the values in df\$b and df\$c into df\$b and
> df\$c3.  the date value in df\$a is NOT between df\$b and df\$c
> (as we copied it in in step 2)  so we can place NA in df\$b and df\$c
>
> also would like to do this going up, too, similar to fill(...,"downup").
> On the end we would want to have this:
>  dfwanted<-data.frame(a=Sys.Date()+1:10,
>  b=Sys.Date()+c(NA,NA,rep(3,7),NA),
>  c=Sys.Date()+c(NA,NA,rep(9,7),NA))
>
>
> thanks,
>
> Andras
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help