[R] converting multiple columns from POSIX* to Date

[Marc Schwartz]

Use inherits() then rather than class():

  DF[] <- lapply(DF, function(x) ifelse(inherits(x, "POSIXt"),
                                        as.Date(x), x))

That should hopefully work better than my first attempt.

HTH,

Marc Schwartz

on 12/10/2008 05:47 PM Farrel Buchinsky wrote:
> I will try that but I am somewhat skeptical since when I go
> class(date.of.birth) I get not just one word but two:  "POSIXt"
> "POSIXct". Will that not mess up the logical test
> 
> When I tried the following:
> lapply(as.list(dataframename),class)=="POSIXt"
> every item was false
> 
> Farrel Buchinsky
> GrandCentral Tel: (412) 567-7870
> 
> 
> 
> 
> 
>> Dear Farrel,
>> Determine the class of each column and apply as.Date() just to those which
>> class is POSIX. For more details see ?class. Here is an example assuming
>> that you're data is named "mydata":
>> apply(mydata, 2, function(x) ifelse( class(x)=="POSIXt" |
>>  class(x)=="POSIXlt" , as.Date(x) , x ) )
>>
>> HTH,
>>
>> Jorge
>>
>>
>>
>> On Wed, Dec 10, 2008 at 6:26 PM, Farrel Buchinsky <fjbuch at gmail.com> wrote:
>>> converting a POSIX class variable to a date class is easy.
>>> dates<-as.Date(x) #where X is of class POSIX
>>> How does one do that to all columns in a data frame that are of POSIX
>>> class and leave all the other columns (integers, factors) as is.
>>>
>>> Feel free to reply with just one or two buzzwords that I could then
>>> search for to find how to do it.
>>>
>>> Farrel Buchinsky
>>>
>>> ______________________________________________
>>> 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.
>>
> 
> ______________________________________________
> 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.