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 <[EMAIL PROTECTED]> 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@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. ______________________________________________ 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.