As Duncan pointed out, this is documented in ?seq.POSIXt: Using ‘"month"’ first advances the month without changing the day: if this results in an invalid day of the month, it is counted forward into the next month: see the examples.
But ?seq.Date gives the impression that the construct Dirk and I tried should work: ## find all 7th of the month between two dates, the last being a 7th. st <- as.Date("1998-12-17") en <- as.Date("2000-1-7") ll <- seq(en, st, by="-1 month") rev(ll[ll > st & ll < en]) is given as an example, and it is not pointed out that this won't work for the 30th of the month. Normally one can extrapolate from patterns given in the examples, and here that isn't true. So perhaps the help should be modified slightly instead? Sarah -- Sarah Goslee http://www.sarahgoslee.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel