Re: [R] return unique values from date/time class object

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Mon 15 Aug 2005 - 18:10:29 EST


Hi Sam

It works for me:

ss<-Sys.time()
sss<-rep(ss,5)
ss<-Sys.time()
sss<-c(sss,ss)

> sss

[1] "2005-08-15 10:04:02 Střední Evropa (letní čas)" "2005-08-15 10:04:02 Střední Evropa (letní čas)"
[3] "2005-08-15 10:04:02 Střední Evropa (letní čas)" "2005-08-15 10:04:02 Střední Evropa (letní čas)"
[5] "2005-08-15 10:04:02 Střední Evropa (letní čas)" "2005-08-15 10:04:35 Střední Evropa (letní čas)"

# six values but only 2 different

> unique(sss)

[1] "2005-08-15 10:04:02 Střední Evropa (letní čas)" "2005-08-15 10:04:35 Střední Evropa (letní čas)"

# 2 values

> str(sss)

'POSIXct', format: chr [1:6] "2005-08-15 10:04:02" "2005-08-15 10:04:02" "2005-08-15 10:04:02" "2005-08-15 10:04:02" "2005- 08-15 10:04:02" ...

# posix format as well

HTH
Petr

On 15 Aug 2005 at 16:57, McClatchie, Sam (PIRSA-SARDI) wrote:

> Background:
> OS: Linux Mandrake 10.1
> release: R 2.0.0
> editor: GNU Emacs 21.3.2
> front-end: ESS 5.2.3
> ---------------------------------
> Colleagues
>
> I have a wind speed time series with a normal frequency distribution
> and a spike in the 5 metres/second bin. The most likely explanation is
> that the instrument was returning duplicate values at this speed. To
> check this, I want to extract all the unique times from the series.
> However, unique() works with vectors and the object is POSIXt class.
> I've looked for a similar function to unique() that will work with
> this class, but have failed to find one.

>
> Any suggestions?
>
> Thanks
>
> Sam
> ----
> Sam McClatchie,
> Biological oceanography
> South Australian Aquatic Sciences Centre
> PO Box 120, Henley Beach 5022
> Adelaide, South Australia
> email <mcclatchie.sam@saugov.sa.gov.au>
> Cellular: 0431 304 497
> Telephone: (61-8) 8207 5448
> FAX: (61-8) 8207 5481
> Research home page <http://www.members.iinet.net.au/~s.mcclatchie/>
>
> /\
> ...>><xX(°>
> //// \\\\
> <°)Xx><<
> ///// \\\\\\
> ><(((°>
> >><(((°> ...>><xX(°>O<°)Xx><<
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html

Petr Pikal
petr.pikal@precheza.cz



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Aug 15 18:18:44 2005

This archive was generated by hypermail 2.1.8 : Sun 23 Oct 2005 - 15:19:48 EST