[R] Feature request for as.Date() function

[smu]

hi,

it fails, when the NA is surrounded by double quotes, which is the
default way of quoting of the write.table command.

x <- read.csv(textConnection('date,value
+ + 2009-01-01,10
+ + 2009-02-01,1
+ + "NA", 3'), colClasses=c("Date", 'integer'))
Fehler in fromchar(x) : 
character string is not in a standard unambiguous format

regards,
 stefan


On Wed, Nov 25, 2009 at 02:56:56PM -0500, jim holtman wrote:
> Seems to work fine in my testing:
> 
> > x <- read.csv(textConnection("date,value
> + 2009-01-01,10
> + 2009-02-01,1
> + 'NA', 3"), colClasses=c("Date", 'integer'))
> >
> > str(x)
> 'data.frame':   3 obs. of  2 variables:
>  $ date :Class 'Date'  num [1:3] 14245 14276 NA
>  $ value: int  10 1 3
> > x <- read.csv(textConnection("date,value
> + 2009-01-01,10
> + 2009-02-01,1
> + NA, 3"), colClasses=c("Date", 'integer'))
> >
> > str(x)
> 'data.frame':   3 obs. of  2 variables:
>  $ date :Class 'Date'  num [1:3] 14245 14276 NA
>  $ value: int  10 1 3
> >
> 
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> On Wed, Nov 25, 2009 at 12:38 PM,
> <nabble.30.miller_2555 at spamgourmet.com> wrote:
> > Hello -
> >
> > I have a csv file with a few date columns. Some of the records have an
> > "NA" character string instead of the date. When I attempt to use
> > read.csv() and typecast the columns using colClasses, I receive the
> > following error:
> >    Error in charToDate(x) :
> >      character string is not in a standard unambiguous format
> >
> > Similarly, the following command produces the same error:
> >    as.Date("NA")
> >
> > However, as.Date(NA) performs as documented.
> >
> > Can we enhance the as.Date() function to convert "NA" strings into NA
> > value prior to type conversion?
> >
> > Thanks!
> >
> > ______________________________________________
> > 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.
> >
> 
> 
> 
> -- 
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
> 
> What is the problem that you are trying to solve?
> 
> ______________________________________________
> 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.
>