[R] Error with strptime

[Stephen Tucker]

you have to use "POSIXct" classes to include date-time objects into data
frames. strptime() returns an object of class of "POSIXlt". when you do the
cbind(), it automatically converts test2 into "POSIXct"

you probably want
bsamp$spltime<-as.POSIXct(strptime(test,format="%d-%B-%y %H:%M"))

(but please be aware of time-zone issues when using "POSIXct" classes). these
documents may help:

http://cran.r-project.org/doc/Rnews/Rnews_2004-1.pdf

=== Also ===
Changes in behavior of POSIXt classes since the aforementioned R News
publication:

http://tolstoy.newcastle.edu.au/R/e2/help/07/04/13626.html
http://tolstoy.newcastle.edu.au/R/e2/help/07/04/13632.html



--- Jean-Louis Abitbol <abitbol at sent.com> wrote:

> Dear All,
> 
> I am trying to convert to POSIXct after pasting a date and a time in
> character format with strptime.
> 
> It is probably obvious but I don't understand why I get an error message
> after
> 
> bsamp$spltime<-strptime(test,format="%d-%B-%y %H:%M")
> 
> whereas I can get what I want if I do it in 2 steps and rbinding ?
> 
> Thanks and best regards, Jean-Louis
> 
> This is the R console output
> 
> > bsamp<-read.table("bsampl2.csv",header=T,sep=";")
> > names(bsamp)<-tolower(names(bsamp))
> > bsamp<-upData(bsamp,drop=c("study"))
> Input object size:       23896 bytes;    15 variables
> Dropped variable         study
> New object size:         23016 bytes;    14 variables
> > bsamp$visitdat<-as.character(bsamp$visitdat)
> > bsamp$samtime<-as.character(bsamp$samtime)
> > bsamp$admtime<-as.character(bsamp$admtime)
> > bsamp$delay<-as.character(bsamp$delay)
> > test<-paste(bsamp$visitdat,bsamp$samtime)
> > test
>   [1] "01-mars-06 11:40" "15-mars-06 11:30" "15-mars-06 15:00"
>   [4] "29-mars-06 11:40" "01-mars-06 11:45" "15-mars-06 11:15"
>   [7] "15-mars-06 14:45" "29-mars-06 12:50" "01-mars-06 11:16"
>  [10] "15-mars-06 11:10" "15-mars-06 14:30" "29-mars-06 11:50"
>  [13] "01-mars-06 11:50" "15-mars-06 11:25" "15-mars-06 14:55"
>  [16] "29-mars-06 11:30" "01-mars-06 11:55" "15-mars-06 11:35"
>  [19] "15-mars-06 "      "29-mars-06 11:45" "01-mars-06 11:09"
>  .....
> 
> 
> > bsamp$spltime<-strptime(test,format="%d-%B-%y %H:%M")
> Erreur dans `$<-.data.frame`(`*tmp*`, "spltime", value = list(sec =
> numeric(0),  :
>         le tableau de remplacement a 9 lignes, le tableau remplacé en a
>         140
> 
> 
> > test2<-strptime(test,format="%d-%B-%y %H:%M")
> > bsamp<-cbind(bsamp,test2)
> > bsamp$test2
>   [1] "2006-03-01 11:40:00 Centre de l'Europe"
>   [2] "2006-03-15 11:30:00 Centre de l'Europe"
>   [3] "2006-03-15 15:00:00 Centre de l'Europe"
>   [4] "2006-03-29 11:40:00 Centre de l'Europe (heure d'été"
>   [5] "2006-03-01 11:45:00 Centre de l'Europe"
>   [6] "2006-03-15 11:15:00 Centre de l'Europe"
>   [7] "2006-03-15 14:45:00 Centre de l'Europe"
>   [8] "2006-03-29 12:50:00 Centre de l'Europe (heure d'été"
>   [9] "2006-03-01 11:16:00 Centre de l'Europe"
>  [10] "2006-03-15 11:10:00 Centre de l'Europe"
>  [11] "2006-03-15 14:30:00 Centre de l'Europe"
>  [12] "2006-03-29 11:50:00 Centre de l'Europe (heure d'été"
>  [13] "2006-03-01 11:50:00 Centre de l'Europe"
>  [14] "2006-03-15 11:25:00 Centre de l'Europe"
>  [15] "2006-03-15 14:55:00 Centre de l'Europe"
>  [16] "2006-03-29 11:30:00 Centre de l'Europe (heure d'été"
>  [17] "2006-03-01 11:55:00 Centre de l'Europe"
>  [18] "2006-03-15 11:35:00 Centre de l'Europe"
>  [19] NA
>  ..........
> > sessionInfo()
> R version 2.4.1 (2006-12-18)
> i386-pc-mingw32
> 
> locale:
>
LC_COLLATE=French_France.1252;LC_CTYPE=French_France.1252;LC_MONETARY=French_France.1252;LC_NUMERIC=C;LC_TIME=French_France.1252
> 
> attached base packages:
> [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"
> [6] "methods"   "base"
> 
> other attached packages:
>          car RColorBrewer       gplots        gdata       gtools
>      "1.2-1"      "0.2-3"      "2.3.2"      "2.3.1"      "2.3.1"
>      lattice        Hmisc      acepack      RWinEdt
>    "0.14-17"      "3.3-1"    "1.3-2.2"      "1.7-5"
> >
> 
> ______________________________________________
> 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.
>