Hello everybody, how can I reduce e.g. 30 days from a date? When I do the following "2011-05-01 CEST" -"2011-04-01 CEST" I get: "Time difference of 30 days" an thats fine. But when I try "2011-05-01 CEST" - 30 I get nonsense. So how can I subtract some days, month or years from a date? thanking you in anticipation Claudia Paladini
Hello,
I don't get it, this seems to work as expected.
d <- as.Date("2011-05-01 CEST")
d - 30
[1] "2011-04-01"
Hope this helps,
Rui Barradas
Em 30-10-2012 10:25, paladini escreveu:> Hello everybody,
> how can I reduce e.g. 30 days from a date?
> When I do the following "2011-05-01 CEST" -"2011-04-01
CEST" I get:
> "Time difference of 30 days"
> an thats fine.
>
> But when I try "2011-05-01 CEST" - 30 I get nonsense.
> So how can I subtract some days, month or years from a date?
>
>
>
> thanking you in anticipation
>
>
> Claudia Paladini
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
Hi> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- > project.org] On Behalf Of paladini > Sent: Tuesday, October 30, 2012 11:26 AM > To: r-help at r-project.org > Subject: [R] subtract a time period from a date > > Hello everybody, > how can I reduce e.g. 30 days from a date? > When I do the following "2011-05-01 CEST" -"2011-04-01 CEST" I get: > "Time difference of 30 days" > an thats fine. > > But when I try "2011-05-01 CEST" - 30 I get nonsense.You subtracted 30 seconds. To subtract 30 days you need to express days in seconds Sys.time()-(30*24*60*60) [1] "2012-09-30 14:05:50 CEST" Regards Petr> So how can I subtract some days, month or years from a date? > > > > thanking you in anticipation > > > Claudia Paladini > > ______________________________________________ > R-help at r-project.org mailing list > 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.
HI, Try this: ?dat1<-"2011-05-01 CEST" ?dat2<-as.POSIXlt(dat1) dat2$mday<-dat2$mday-30 dat2 #[1] "2011-04-01" A.K. ----- Original Message ----- From: paladini <paladini at beuth-hochschule.de> To: r-help at r-project.org Cc: Sent: Tuesday, October 30, 2012 6:25 AM Subject: [R] subtract a time period from a date Hello everybody, how can I reduce e.g. 30 days from a date? When I do? the following? "2011-05-01 CEST" -"2011-04-01 CEST" I get: "Time difference of 30 days" an thats fine. But when I try "2011-05-01 CEST" - 30 I get nonsense. So how can I subtract some days, month or years from a date? thanking you in anticipation Claudia Paladini ______________________________________________ R-help at r-project.org mailing list 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.