Re: [R] Check for date variable in a arbitrary dataset

From: Harsh <singhalblr_at_gmail.com>
Date: Tue, 25 Nov 2008 12:58:04 +0530

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 <ggrothendieck_at_gmail.com> wrote:
> The classes of the columns are:
>
> sapply(DF, class)
>
>
> On Mon, Nov 24, 2008 at 3:39 AM, Harsh <singhalblr_at_gmail.com> 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_at_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.
>>
>



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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. Received on Tue 25 Nov 2008 - 07:31:19 GMT

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