If its a date you should ensure its of "Date" class prior to performing this analysis rather than representing it as something else. See R News 4/1.
On Tue, Nov 25, 2008 at 2:28 AM, Harsh <[EMAIL PROTECTED]> wrote: > Thank you Gabor for your prompt reply. > > I had tried checking for class, but it returns three types of my > dataset, which are numeric, integer and character. > The problem with that is, I need to classify some columns as > categorical and in doing so I have a cut off of 100 or less unique > values in the column/variable. > > In case of dates, I cannot consider it to be categorical, since in a > 100,000 row dataset, dates will take more than 100 unique values, and > checking for its class will return character. > If i could somehow know it was a date, then I could provide a Time > Series analysis for it. > The same may hold true for, example serial number. > > I tried using regexpr to check for the presence of "/" OR "-" to check > for it being a date column, but it returns the presence of the first > "/" which if is at the position 3, could mean a date format of > dd/mm/yyyy or mm/dd/yyyy. > > This would be a long winded approach, and I am looking for something > more efficient. > > Thank you for your time. > > > Harsh Singhal > > > On Mon, Nov 24, 2008 at 7:06 PM, Gabor Grothendieck > <[EMAIL PROTECTED]> wrote: >> The classes of the columns are: >> >> sapply(DF, class) >> >> >> On Mon, Nov 24, 2008 at 3:39 AM, Harsh <[EMAIL PROTECTED]> wrote: >>> Hello, >>> This is my first time posting to the R-help list and I apologize for >>> the apparent triviality of my query. >>> I am creating an R script to create Univariate Exploratory Analysis of >>> a input dataset (No meta-data to provide extra information about each >>> column) >>> . >>> Providing summary statistics is possible in case of numeric data and >>> using all.is.numeric() from the Hmisc package allows me to filter out >>> those columns with alpha-numeric content. >>> >>> I have tried to check if a column is a date field or not, but have not >>> been able to do so. Are Regular Expressions the only answer? I've also >>> looked for CRAN packages but haven't found any. >>> Bering a newbie user of R, I do not possess the requisite knowledge to >>> write my own function for the above objective. >>> >>> Thank you for your time >>> Harsh >>> Decisions Systems Group >>> Mu Sigma Inc. >>> Chicago, IL >>> >>> ______________________________________________ >>> 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. >>> >> > ______________________________________________ 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.
