# [R] timeAlign

Gabor Grothendieck ggrothendieck at gmail.com
Tue Apr 11 02:54:27 CEST 2006

```On 4/10/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> Try this.
>
> dd <- Sys.time()  # test data
>
> lt <- as.POSIXlt(dd)
>
> ISOdate(1900+lt\$year, 1, 1, 0, tz = "")
> ISOdate(1901+lt\$year, 1, 1, 0, tz = "")
>
> seq(now, length = 2, by = paste("-", lt\$wday, " day", sep =""))[2]
> seq(now, length = 2, by = paste(7-lt\$wday, "day"))[2]

The last two lines should be (same as above but the variable
name is called lt):

seq(lt, length = 2, by = paste("-", lt\$wday, " day", sep =""))[2]
seq(lt, length = 2, by = paste(7-lt\$wday, "day"))[2]

>
> with(lt, ISOdate(1901+year, mon, mday, 0, tz = ""))
> with(lt, ISOdate(1901+year, mon, mday, 23, 59, 59, tz = ""))+1
>
>
>
> On 4/10/06, Omar Lakkis <uofiowa at gmail.com> wrote:
> > I use POSIXct for datetimes. Is thee a timeAlign function that I can
> > use where :
> >
> > align by year
> >      direction -1 ==> start of this year
> >      direction 1  ==> start of next year
> > align by week
> >      direction -1 ==> date on last sunday
> >      direction 1  ==> date on next sunday
> > align by day
> >      direction -1 ==> time at past midnight
> >      direction 1  ==> time at this comming midnight
> >
> > ______________________________________________
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> > https://stat.ethz.ch/mailman/listinfo/r-help