[R] Sorting a vector by date

[Prof Brian Ripley]

On Fri, 12 Sep 2003, Michael Kirschbaum wrote:

> Hello out there....
> 
> Again I have a problem and I stuck...
> 
> How can  I sort a vector of dates?
> 
> For example I have the vector
> 
> a<-ISOdate(2001, 1, 1) + 70*86400*runif(10)

> How can this vector be sorted chronological?

a[sort.list(a)]


> And what's the function I should work with to handle  these entries?
> (in sense of:  which(a>2001-01-04) or somehting like that)

No function, just make sure you use *dates*, as in

which(a > as.POSIXct("2001-01-04"))


-- 
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