[R] Time and Date formatting

[Jeff Newmiller]

a) In some analyses, date/time values are only needed to identify data records, in which case a simple paste is enough.

b) If you ARE going to need to to calculate or plot date/time and choose to use POSIXt types to represent it, make a habit of always setting your "local" (local to the computer process, at least) timezone to match the timezone of your data (e.g. Sys.setenv( TZ="Etc/GMT+8")) at least for the duration of this conversion to avoid mysterious NA values in the POSIX data. If you don't want to be bothered with time zones, then use the chron library as mentioned in ?as.POSIXct.
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Sent from my phone. Please excuse my brevity.

Rui Barradas <ruipbarradas at sapo.pt> wrote:

>Hello,
>
>Forgot to add strptime, like you had noted.
>
>strptime(paste(DATE, TIME), format = "%d/%m/%Y %H:%M")
>
>
>Rui Barradas
>
>Em 23-04-2013 19:54, Rui Barradas escreveu:
>> Hello,
>>
>> See if any of the following will do.
>>
>>
>> DATE <- "14/07/2010"
>> TIME <-  "20:21"
>> paste(DATE, TIME)
>> as.POSIXct(paste(DATE, TIME), format = "%d/%m/%Y %H:%M")
>>
>>
>> Hope this helps,
>>
>> Rui Barradas
>>
>> Em 23-04-2013 19:46, Ayyappa Chaturvedula escreveu:
>>> Dear Group,
>>>
>>> I have  a problem with time date formatting.  I have Date and Time
>in
>>> different columns in a .csv file and want to have a column with Date
>and
>>> Time together.  I could format the date into the right mode using
>>> strptime
>>> and as.Date functions.  I am not able to do that with TIME column. I
>>> appreciate your help in solving this issue.  Currently the TIME
>column is
>>> in character mode.
>>>
>>>
>>>    DATE              TIME                   DATETIME
>>> 14/07/2010       20:21    *Want:* 14/07/2010  20:11
>>>
>>> Thanks in advance for your help.
>>>
>>> Regards,
>>> Ayyappa
>>>
>>>     [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
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>>> 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.
>>>
>>
>> ______________________________________________
>> 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.
>
>______________________________________________
>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.