[R] character to time problem

Gabor Grothendieck ggrothendieck at gmail.com
Fri Jun 8 00:01:25 CEST 2007


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  (Yes I know I'm out of date but I don't like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
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>



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