[R] Extracting dates to create a new variable

Ulrik Stervbo ulrik.stervbo at gmail.com
Mon Aug 8 21:25:36 CEST 2016


Getting the dates of the departments CC, DD, FF can be done with

subset(df, deps %in% c("CC", "DD", "FF"))

I am not sure how you intend to match these identified dates with other
departments? From your example you sometimes replace earlier dates,
sometimes later dates.

HTH
Ulrik

On Mon, 8 Aug 2016 at 20:23 Farnoosh Sheikhi via R-help <
r-help at r-project.org> wrote:

> Hi there,
> I have a data set like below and wanted to create a new date variable by
> extracting the dates for specific departments.I want to extract the dates
> for departments CC, DD, FF,  put it in a new column and repeat it for other
> unique IDs.
> Subject<- c("2", "2", "2", "3", "3", "3", "4", "4", "5", "5", "5",
> "5")dates<-seq(as.Date('2011-01-01'),as.Date('2011-01-12'),by =
> 1) deps<-c("A", "B", "CC", "C", "CC", "A", "F", "DD", "A", "F", "FF",
> "D")df <- data.frame(Subject, dates, deps)df
> The final data set should look like this:newdate<-c(" 2011-01-03",
>  "2011-01-03",  "2011-01-03", "2011-01-05", "2011-01-05", "2011-01-05" ,
> "2011-01-08", "2011-01-08", "2011-01-08", "2011-01-11", "2011-01-11",
> "2011-01-11")final<-data.frame(Subject, dates, deps, newdate)final
> I really appreciate any help.
>  Best,Farnoosh
>
>
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