Dear list, "+" (and "-") being defined for difftime class, I expected mean() to return something sensible. This is only half-true :
> mean(c(1:5, 5:1),na.rm=TRUE) [1] 3 > mean(as.difftime(c(1:5, 5:1),unit="mins"),na.rm=TRUE) Time difference of 3 mins Fine so far. However : > mean(c(1:5, NA,5:1),na.rm=TRUE) [1] 3 > mean(as.difftime(c(1:5, NA,5:1),unit="mins"),na.rm=TRUE) Time difference of NA mins Ouch ! Curiously, var(), max() and min() behave as expected. What's so special with mean() ? > RSiteSearch("mean difftime") [ ... doesn't return anything relevant ] NB : this isn't done for the hell of it. I intended to replace some missing dates, with something computed from other dates and mean time intervals). Any thoughs ? Emmanuel Charpentier ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.