Hello, I have a data set with dates stored as a factor with levels coded as, for example "01/03/1996" I tried the following: onset <- strptime(as.character(cf$dx.dt), format="%m%d%Y") where cf$dx.dt are the dates in the data frame cf. For output, I get NA for every entry. If it matters, I'm running the fink version of R 1.6.1 on a powerbook G4 with OS 10.2.2. I have little experience dealing with dates in R. Is there a reference that discusses the general issues? Any help would be much appreciated. Thanks, John -- John Carew <jcarew@stat.wisc.edu> Department of Statistics University of Wisconsin--Madison http://www.stat.wisc.edu/~jcarew
Date conversion problems
3 messages · John Carew, Don MacQueen, Thomas Lumley
Try format="%m/%d/%Y" The help pages are pretty good, and the examples in ?strptime show something quite similar to your case. Vol. 1/2 of R News (available at the R website) has the article that introduced the POSIXt classes. -Don
Hello, I have a data set with dates stored as a factor with levels coded as, for example "01/03/1996" I tried the following: onset <- strptime(as.character(cf$dx.dt), format="%m%d%Y") where cf$dx.dt are the dates in the data frame cf. For output, I get NA for every entry. If it matters, I'm running the fink version of R 1.6.1 on a powerbook G4 with OS 10.2.2. I have little experience dealing with dates in R. Is there a reference that discusses the general issues? Any help would be much appreciated. Thanks, John -- John Carew <jcarew@stat.wisc.edu> Department of Statistics University of Wisconsin--Madison http://www.stat.wisc.edu/~jcarew
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-------------------------------------- Don MacQueen Environmental Protection Department Lawrence Livermore National Laboratory Livermore, CA, USA --------------------------------------
On Sun, 2 Feb 2003, John Carew wrote:
Hello, I have a data set with dates stored as a factor with levels coded as, for example "01/03/1996" I tried the following: onset <- strptime(as.character(cf$dx.dt), format="%m%d%Y")
If the dates look like "01/03/1996" then the format is "%m/%d/%Y" -thomas