Hi: Perhaps you were looking for something like this:
table(cut(mydata[[1]], breaks=seq(from = as.Date("2008-06-26"), to = as.Date("2009-06-26"), by = 'month'))) 2008-06-26 2008-07-26 2008-08-26 2008-09-26 2008-10-26 2008-11-26 2008-12-26 30 31 31 30 31 30 31 2009-01-26 2009-02-26 2009-03-26 2009-04-26 2009-05-26 31 28 31 30 31 Considering that your data range from May 2007 to mid-November 2009, a way to generate monthly tables (or any set of common breaks you want) for all components of the list can be done as follows: f <- function(x) table(cut(x, breaks = seq(from = as.Date('2007-05-01'), to = as.Date('2009-12-01'), by = 'month'))) lapply(mydata, f) This is simply intended to get you started in case you wanted to map your problem across multiple list components. HTH, Dennis On Mon, Jan 17, 2011 at 11:16 PM, Simon Kiss <simonjk...@yahoo.ca> wrote: > Dear Colleagues, > I have a data set that looks as below. I'd like to count the number of > dates in a series of arbitrary ranges (breaks) i.e. not pre-defined breaks > such as months, quarters or years. table(format()) produces ideally > formatted output, but table() does not appear to accept arbitrary ranges. > I also tried converting the dates to numeric and using histogram to try to > get the data, but that doesn't work either. Cut appears to accept an > arbitrary range, but I could only get it to produce NAs. > > Any suggestions? Yours, Simon Kiss > > mydata<-list(x=seq(as.Date("2007-05-01"), as.Date("2009-09-10"),"days"), > y=seq(as.Date("2007-06-16"), as.Date("2009-11-12"),"days")) > table(format(mydata[[1]], "%Y")) > t_1<-hist(as.numeric(mydata[[1]], breaks=c("14056", "14421")))$counts > cut(mydata[[1]], breaks=c(as.Date("2008-06-26"), ("2009=06-26"))) > > > ********************************* > Simon J. Kiss, PhD > Assistant Professor, Wilfrid Laurier University > 73 George Street > Brantford, Ontario, Canada > N3T 2C9 > Cell: +1 519 761 7606 > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.