Truncating dates (and other date-time manipulations)
See ?cut.Date In the zoo package see: ?as.yearmon ?as.yearqtr ?aggregate.zoo and the many examples in: ?plot.zoo ?xyplot.zoo as well as the three zoo vignettes. Also in the xts package look at ?to.period For regularly spaced series the tis package supports a wide variety of time bases and can convert among them. There are as.zoo.tis and as.tis.zoo routines in zoo and tis; also, xts is a subclass of zoo so all these packages can work together.
On Thu, Sep 11, 2008 at 11:02 AM, hadley wickham <h.wickham at gmail.com> wrote:
Dear all, I've been struggling to perform common operations on dates that I need to be able to correct draw date-time scales - in particular I need to be able to round/truncate/ceiling dates to arbitrary precision - e.g. to weeks, months or years (or multiples thereof). I haven't been able to find anything to do this in base R (trunc.Date only truncates to sub-day units), or in the date related contributed packages I've looked in (e.g. chron). Have I missed something? Otherwise, I have been working on a bottom up set of functions to make date manipulation easier - http://gist.github.com/10238. These should work for all date-time types and I've tried to use a consistent naming scheme and consistent output conventions. This seems like a rather small bundle of functions to be worth turning into a package, so I was wondering if anyone would be interested in adopting them into an existing date-time related package. Regards, Hadley -- http://had.co.nz/
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