return unique values from date/time class object
On Mon, 15 Aug 2005, McClatchie, Sam (PIRSA-SARDI) wrote:
Background: OS: Linux Mandrake 10.1 release: R 2.0.0
Time for an update.
editor: GNU Emacs 21.3.2 front-end: ESS 5.2.3 --------------------------------- Colleagues I have a wind speed time series with a normal frequency distribution and a spike in the 5 metres/second bin. The most likely explanation is that the instrument was returning duplicate values at this speed. To check this, I want to extract all the unique times from the series. However, unique() works with vectors and the object is POSIXt class. I've looked for a similar function to unique() that will work with this class, but have failed to find one.
foo[!duplicated(unclass(foo))] works, for POSIXct (POSIXt is a virtual class covering that and POSIXlt: for the latter convert to POSIXct).
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