[R] Time rather than dates?
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue May 30 14:26:27 CEST 2006
On Tue, 30 May 2006, Robert Lundqvist wrote:
> Using strptime() and other functions for dates has been very helpful with
> the kind of data I often work with. However, I haven't found out how time
> as such should be specified. All my attempts result in time *and* date:
>
>> treatment_time<-c("01:02:03","02:03:04") # hours:minutes:seconds
>> time.2<-strptime(treatment_time,format="%H:%M:%S")
>
>> time.2
> [1] "1900-01-01 01:02:03" "1900-01-01 02:03:04"
>
> Why the 1900-...? I had hoped for some easy conversion from time to
> numeric data and possibly back. Assistance would be appreciated.
You asked to print a datetime object of class POSIXlt, and unspecified
fields are set to their earliest values. But printing is only part of the
story.
What do you actually want from this?
3600*time.2$hour + 60*time.2$min + time.2$sec
gives you the number of seconds since midnight, for example. See
?DateTimeClasses
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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