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Aimin Yan

2009-Mar-14 12:52 UTC

[R] Format about Date and time

I have a data set like this:

 > head(FormatedData)
     ID Target Actual     Date     Time
1 2030      0  -57.0 12/20/08 17:03:00
2 2030     90   90.0 12/20/08 18:41:00
3 2030     45   43.8 12/21/08 14:36:00
4 2030      0  -23.8 12/21/08 19:30:00
5 2030     90   90.2 12/21/08 21:48:00
6 2030     45   48.6 12/22/08 13:02:00

I wan to convert the format of Date and Time, so I did this:

pdate <- as.POSIXct(strptime(FormatedData$Date,"%m/%d/%Y"))
ptime <- as.POSIXct(strptime(FormatedData$Time,"%H:%M:%S"))

but I get the following format:

 > head(NewFormatedData)
     ID Target Actual     Date     Time   pdate               ptime
1 2030      0  -57.0 12/20/08 17:03:00 8-12-20 2009-03-14 17:03:00
2 2030     90   90.0 12/20/08 18:41:00 8-12-20 2009-03-14 18:41:00
3 2030     45   43.8 12/21/08 14:36:00 8-12-21 2009-03-14 14:36:00
4 2030      0  -23.8 12/21/08 19:30:00 8-12-21 2009-03-14 19:30:00
5 2030     90   90.2 12/21/08 21:48:00 8-12-21 2009-03-14 21:48:00
6 2030     45   48.6 12/22/08 13:02:00 8-12-22 2009-03-14 13:02:00

in ptime, it includes the current date, I don't want this,
actually, I want to have the following formats:

     ID Target Actual     Date     Time    pdate               ptime
1 2030      0  -57.0 12/20/08 17:03:00  2008-12-20      17:03:00
2 2030     90   90.0 12/20/08 18:41:00 2008-12-20      18:41:00
3 2030     45   43.8 12/21/08 14:36:00  2008-12-21     14:36:00
4 2030      0  -23.8 12/21/08 19:30:00   2008-12-21     19:30:00
5 2030     90   90.2 12/21/08 21:48:00  2008-12-21      21:48:00
6 2030     45   48.6 12/22/08 13:02:00  2008-12-22     13:02:00

Does anyone know how to do these?

David Winsemius

2009-Mar-14 15:26 UTC

head link

[R] Format about Date and time

On Mar 14, 2009, at 8:52 AM, Aimin Yan wrote:
> I have a data set like this:
>
> > head(FormatedData)
>    ID Target Actual     Date     Time
> 1 2030      0  -57.0 12/20/08 17:03:00
> 2 2030     90   90.0 12/20/08 18:41:00
> 3 2030     45   43.8 12/21/08 14:36:00
> 4 2030      0  -23.8 12/21/08 19:30:00
> 5 2030     90   90.2 12/21/08 21:48:00
> 6 2030     45   48.6 12/22/08 13:02:00
>
> I wan to convert the format of Date and Time, so I did this:
>
> pdate <- as.POSIXct(strptime(FormatedData$Date,"%m/%d/%Y"))
You do not have a %Y format for years.

See if this minimal example helps::
timedf <- data.frame(Date1 = "12/20/08", Time1=
"17:03:00")
strptime( with(timedf, paste(Date1,Time1) ), format="%m/%d/%y
%H:%M:%S")
# [1] "2008-12-20 17:03:00"
>
> ptime <- as.POSIXct(strptime(FormatedData$Time,"%H:%M:%S"))
>
> but I get the following format:
>
> > head(NewFormatedData)
>    ID Target Actual     Date     Time   pdate               ptime
> 1 2030      0  -57.0 12/20/08 17:03:00 8-12-20 2009-03-14 17:03:00
> 2 2030     90   90.0 12/20/08 18:41:00 8-12-20 2009-03-14 18:41:00
> 3 2030     45   43.8 12/21/08 14:36:00 8-12-21 2009-03-14 14:36:00
> 4 2030      0  -23.8 12/21/08 19:30:00 8-12-21 2009-03-14 19:30:00
> 5 2030     90   90.2 12/21/08 21:48:00 8-12-21 2009-03-14 21:48:00
> 6 2030     45   48.6 12/22/08 13:02:00 8-12-22 2009-03-14 13:02:00
>
> in ptime, it includes the current date, I don't want this,
> actually, I want to have the following formats:
>
>    ID Target Actual     Date     Time    pdate               ptime
> 1 2030      0  -57.0 12/20/08 17:03:00  2008-12-20      17:03:00
> 2 2030     90   90.0 12/20/08 18:41:00 2008-12-20      18:41:00
> 3 2030     45   43.8 12/21/08 14:36:00  2008-12-21     14:36:00
> 4 2030      0  -23.8 12/21/08 19:30:00   2008-12-21     19:30:00
> 5 2030     90   90.2 12/21/08 21:48:00  2008-12-21      21:48:00
> 6 2030     45   48.6 12/22/08 13:02:00  2008-12-22     13:02:00
>
> Does anyone know how to do these?
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT

Gabor Grothendieck

2009-Mar-14 16:32 UTC

head link

[R] Format about Date and time

library(chron)
Lines <- " ID Target Actual     Date     Time
1 2030      0  -57.0 12/20/08 17:03:00
2 2030     90   90.0 12/20/08 18:41:00
3 2030     45   43.8 12/21/08 14:36:00
4 2030      0  -23.8 12/21/08 19:30:00
5 2030     90   90.2 12/21/08 21:48:00
6 2030     45   48.6 12/22/08 13:02:00"

DF <- read.table(textConnection(Lines), header = TRUE, as.is = TRUE)
dt <- chron(DF$Date, DF$Time)
DF$pdate <- format(as.Date(dt))
DF$ptime <- format(dt - dates(dt))

This gives:
> DF    ID Target Actual     Date     Time      pdate    ptime
1 2030      0  -57.0 12/20/08 17:03:00 2008-12-20 17:03:00
2 2030     90   90.0 12/20/08 18:41:00 2008-12-20 18:41:00
3 2030     45   43.8 12/21/08 14:36:00 2008-12-21 14:36:00
4 2030      0  -23.8 12/21/08 19:30:00 2008-12-21 19:30:00
5 2030     90   90.2 12/21/08 21:48:00 2008-12-21 21:48:00
6 2030     45   48.6 12/22/08 13:02:00 2008-12-22 13:02:00

See R News 4/1 for info on dates.

Also, why do you want to store formatted dates in the first place?

On Sat, Mar 14, 2009 at 8:52 AM, Aimin Yan <aiminy at iastate.edu>
wrote:> I have a data set like this:
>
>> head(FormatedData)
> ? ?ID Target Actual ? ? Date ? ? Time
> 1 2030 ? ? ?0 ?-57.0 12/20/08 17:03:00
> 2 2030 ? ? 90 ? 90.0 12/20/08 18:41:00
> 3 2030 ? ? 45 ? 43.8 12/21/08 14:36:00
> 4 2030 ? ? ?0 ?-23.8 12/21/08 19:30:00
> 5 2030 ? ? 90 ? 90.2 12/21/08 21:48:00
> 6 2030 ? ? 45 ? 48.6 12/22/08 13:02:00
>
> I wan to convert the format of Date and Time, so I did this:
>
> pdate <- as.POSIXct(strptime(FormatedData$Date,"%m/%d/%Y"))
> ptime <- as.POSIXct(strptime(FormatedData$Time,"%H:%M:%S"))
>
> but I get the following format:
>
>> head(NewFormatedData)
> ? ?ID Target Actual ? ? Date ? ? Time ? pdate ? ? ? ? ? ? ? ptime
> 1 2030 ? ? ?0 ?-57.0 12/20/08 17:03:00 8-12-20 2009-03-14 17:03:00
> 2 2030 ? ? 90 ? 90.0 12/20/08 18:41:00 8-12-20 2009-03-14 18:41:00
> 3 2030 ? ? 45 ? 43.8 12/21/08 14:36:00 8-12-21 2009-03-14 14:36:00
> 4 2030 ? ? ?0 ?-23.8 12/21/08 19:30:00 8-12-21 2009-03-14 19:30:00
> 5 2030 ? ? 90 ? 90.2 12/21/08 21:48:00 8-12-21 2009-03-14 21:48:00
> 6 2030 ? ? 45 ? 48.6 12/22/08 13:02:00 8-12-22 2009-03-14 13:02:00
>
> in ptime, it includes the current date, I don't want this,
> actually, I want to have the following formats:
>
> ? ?ID Target Actual ? ? Date ? ? Time ? ?pdate ? ? ? ? ? ? ? ptime
> 1 2030 ? ? ?0 ?-57.0 12/20/08 17:03:00 ?2008-12-20 ? ? ?17:03:00
> 2 2030 ? ? 90 ? 90.0 12/20/08 18:41:00 2008-12-20 ? ? ?18:41:00
> 3 2030 ? ? 45 ? 43.8 12/21/08 14:36:00 ?2008-12-21 ? ? 14:36:00
> 4 2030 ? ? ?0 ?-23.8 12/21/08 19:30:00 ? 2008-12-21 ? ? 19:30:00
> 5 2030 ? ? 90 ? 90.2 12/21/08 21:48:00 ?2008-12-21 ? ? ?21:48:00
> 6 2030 ? ? 45 ? 48.6 12/22/08 13:02:00 ?2008-12-22 ? ? 13:02:00
>
> Does anyone know how to do these?
>
> ______________________________________________
> R-help at 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.
>

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