Hi, On Wed, Jun 22, 2011 at 11:40 AM, Alexander Shenkin <ashen...@ufl.edu> wrote: >> is.na(strptime("5/2/1992", format="%m/%d/%Y")) > [1] FALSE >> is.na(strptime("5/3/1992", format="%m/%d/%Y")) > [1] TRUE
I can't reproduce your problem on R 2.13.0 on linux: > strptime("5/2/1992", format="%m/%d/%Y") [1] "1992-05-02" > is.na(strptime("5/2/1992", format="%m/%d/%Y")) [1] FALSE > strptime("5/3/1992", format="%m/%d/%Y") [1] "1992-05-03" > is.na(strptime("5/3/1992", format="%m/%d/%Y")) [1] FALSE My suspicion is that you imported the data from a spreadsheet and there's some formatting glitch that's not showing up. If you type the string "5/3/1992" into the command by hand, do you still get the same result? If so, then we need to know your OS and version of R, at least. > Any idea what's going on with this? Running strptime against all dates > from around 1946, only 5/3/1992 was converted as "NA". Even stranger, > it still seems to have a value associated with it (even though is.na > thinks it's NA): > >> strptime("5/3/1992", format="%m/%d/%Y") > [1] "1992-05-03" This makes no sense to me. Sarah -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ 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.