It sounds like that column of data is not of type "date" at all. You cannot have one element of a column different from the rest of the column. In a data.frame you can have different types of data in different columns but not in the same column.
Where mydata is your data.frame do : str(mydata) This will give you a listing of the type of data in each column in your data.frame. My guess would be that R has read in that column as character or factor. Just because it looks like a date on the screen does not mean it is one. You probably will have to convert it to a date. See ?as.Date for one way to do this. You might also want to have a look at the lubridate package. For further reference https://github.com/hadley/devtools/wiki/Reproducibility http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example In particular for a question like yours, supplying some sample data using dput() would have really helped. If you are still having a problem do : dput(mydata) and paste the output into the email. The reader can then paste the data into their version of R and see exactly what you are working with. For large datasets usually a sample amoutnt will do , so dput(head(mydata, 100) for example will supply 100 rows of data. Below is a example of a data.frame in dput format. Just copy and paste it into R and you will have a new date.frame John Kane Kingston ON Canada ##====================dput file=================== dat1 <- structure(list(xx = structure(c(5L, 6L, 10L, 9L, 17L, 10L, 15L, 16L, 5L, 14L, 5L, 7L, 17L, 6L, 11L, 8L, 5L, 3L, 1L, 17L, 7L, 10L, 5L, 15L, 15L, 16L, 17L, 14L, 8L, 13L, 12L, 13L, 18L, 9L, 5L, 2L, 1L, 16L, 1L, 1L, 1L, 16L, 4L, 10L, 1L, 18L, 18L, 14L, 13L, 4L), .Label = c("a", "b", "d", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t"), class = "factor"), yy = c(0.332304663767243, -1.77867401940838, 0.828612337938625, 0.481702424196278, 0.0825987297345907, -1.40224568135063, -0.243388884456876, 0.0865304079310024, -0.124012796374592, -0.0107544463484595, -0.542307211820575, 0.0129727866797914, -0.478553152291621, -1.63895681984396, 0.0911014618211326, -0.890215628553797, -1.42140590396317, 0.202337039384179, 1.30089052407852, 0.07517013402338, -0.807355878474237, 1.12978841894929, 0.154740986108198, 0.21209595540936, 0.65345449749952, 0.533479658343466, 0.665882552612018, -0.604444572360781, -0.0971202279326936, -0.862179166296771, -0.977706435316816, 0.559634439503645, 0.0320050874597674, -1.65502174652502, 0.853046541850183, -0.801904205812903, -0.820335448022446, -0.912451936657161, 0.222469916395761, 0.0168002536713376, -0.218537143966283, 1.00191128410043, -0.430912734152427, -1.1327880971227, -0.664284053548425, 1.3082467197158, 1.46148850229679, -1.11954785811615, -1.61706514557631, 0.604530320200236)), .Names = c("xx", "yy"), row.names = c(NA, -50L), class = "data.frame") ##===================end dput file > -----Original Message----- > From: jeffj...@worldvision.org > Sent: Thu, 29 Aug 2013 20:29:54 -0700 > To: r-help@r-project.org > Subject: [R] Validating data type > > > > I'm very new to R. I have a data file that I have read in via read.csv. I > expect one of the "columns" to be of type date for example. However at > least one value in that column is not of date type. I know this because > another program I am trying to process the file with is erroring, yet it > doesn't tell me what row/value is erroring. Does R have a way to: treat > column x as date type, and print out all values/row numbers do not > conform > to that type for that specified column? > > Many thanks! > Jeff > [[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. ____________________________________________________________ TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5 Capture screenshots, upload images, edit and send them to your friends through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST! ______________________________________________ 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.
