Class for time of day?
There is a times class in the chron package. Times are measured in fractions of a day so 1/24 is one hour.
library(chron) dt <- Sys.time() tt <- times(format(dt, "%H:%M:%S")) tt
[1] 12:27:46
tt + 1/24
[1] 13:27:46 There is an article on dates and times in R News 4/1. On Wed, May 20, 2009 at 10:57 AM, Stavros Macrakis
<macrakis at alum.mit.edu> wrote:
What is the recommended class for time of day (independent of calendar date)? And what is the recommended way to get the time of day from a POSIXct object? (Not a string representation, but a computable representation.) I have looked in the man page for DateTimeClasses, in the Time Series Analysis Task View and in Spector's Data Manipulation book but haven't found these. Clearly I can create my own Time class and hack around with the internal representation of POSIXct, e.g. ? ?days <- unclass(d)/(24*3600) ? ?days-floor(days) and write print.Time, `-.Time`, etc. etc. but I expect there is already a standard class or CRAN package. ? ? ? ? ? -s ? ? ? ?[[alternative HTML version deleted]]
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