[R] character to time problem

[John Kane]

Looks much better. I seldom use dates for much and
didn't think to look at the sort.POSIXlt function.

If I understand this correctly the sort.POSIXlt with
na.last = FALSE is dropping all the NAs.  Very nice.


--- Gabor Grothendieck <ggrothendieck at gmail.com>
wrote:

> Perhaps you want one of these:
> 
> > sort(as.Date(aa$times, "%d/%m/%Y"))
> [1] "1995-03-02" "2001-05-12" "2007-02-14"
> 
> > sort(as.Date(aa$times, "%d/%m/%Y"), na.last =
> TRUE)
> [1] "1995-03-02" "2001-05-12" "2007-02-14" NA       
>    NA
> [6] NA
> 
> 
> On 6/7/07, John Kane <jrkrideau at yahoo.ca> wrote:
> > I am trying to clean up some dates and I am
> clearly
> > doing something wrong.  I have laid out an example
> > that seems to show what is happening with the
> "real"
> > data.  The  coding is lousy but it looks like it
> > should have worked.
> >
> > Can anyone suggest a) why I am getting that NA
> > appearing after the strptime() command and b) why
> the
> > NA is disappearing in the sort()? It happens with
> > na.rm=TRUE  and na.rm=FALSE
> > -------------------------------------------------
> > aa  <- data.frame( c("12/05/2001", " ",
> "30/02/1995",
> > NA, "14/02/2007", "M" ) )
> > names(aa)  <- "times"
> > aa[is.na(aa)] <- "M"
> > aa[aa==" "]  <- "M"
> > bb <- unlist(subset(aa, aa[,1] !="M"))
> > dates <- strptime(bb, "%d/%m/%Y")
> > dates
> > sort(dates)
> > --------------------------------------------------
> >
> > Session Info
> > R version 2.4.1 (2006-12-18)
> > i386-pc-mingw32
> >
> > locale:
> > LC_COLLATE=English_Canada.1252;
> > LC_CTYPE=English_Canada.1252;
> > LC_MONETARY=English_Canada.1252;
> > LC_NUMERIC=C;LC_TIME=English_Canada.1252
> >
> > attached base packages:
> > [1] "stats"     "graphics"  "grDevices" "utils"
> > "datasets"  "methods"   "base"
> >
> > other attached packages:
> >  gdata   Hmisc
> > "2.3.1" "3.3-2"
> >
> >  (Yes I know I'm out of date but I don't like
> > upgrading just as I am finishing a project)
> >
> > Thanks
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch 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.
> >
>