[R] as.Date

[Ogbos Okike]

Dear ALL,
Thank you so much for your contributions.
I have made some progress. Below is a simple script I gleaned from
your kind responses:
Sys.setenv(TZ="Etc/GMT")
dates <- c("02/27/92", "02/27/92", "01/14/92", "02/28/92", "02/01/92")
     times <- c("23:0:0", "22:0:0", "01:00:00", "18:0:0", "16:0:0")
     x <- paste(dates, times)
     aa<-strptime(x, "%m/%d/%y %H:%M:%S")
bb<-1:5
plot(aa, bb)

I tried plotting my result and I got what I am looking for. I think I
am almost there.

I am, however, stuck here. My data is a large file and the form
differs a little from the example I used. The quotation marks in both
date and time is my headache now. Such inverted commas are not in my
data. I can with awk transform my data to get exactly something like
dd/mm/yy. But I wont know how to make the data appear in quotation
mark in R. I will once more be glad for any more help.
Ogbos

PS: I am still afraid of this forum. Please direct me to the right
forum if this is not ok. Thanks again.


On 4/18/16, peter dalgaard <pdalgd at gmail.com> wrote:
> The most important thing is that Date objects by definition do not include
> time of day. You want to look at ISOdatetime() and as.POSIXct() instead. And
> beware daylight savings time issues.
>
> -pd
>
> On 18 Apr 2016, at 15:09 , Ogbos Okike <giftedlife2014 at gmail.com> wrote:
>
>> Dear All,
>>
>> I have a data set containing year, month, day and counts as shown below:
>> data <- read.table("data.txt", col.names = c("year", "month", "day",
>> "counts"))
>> Using the formula below, I converted the data to as date and plotted.
>>
>> new.century <- data$year < 70
>>
>> data$year <- ifelse(new.century, data$year + 2000, data$year + 1900)
>>
>> data$date <- as.Date(ISOdate(data$year, data$month, data$day))
>>
>> The form of the data is:
>> 16 1 19 9078
>> 16 1 20 9060
>> 16 1 21 9090
>> 16 1 22 9080
>> 16 1 23 9121
>> 16 1 24 9199
>> 16 1 25 9289
>> 16 1 26 9285
>> 16 1 27 9245
>> 16 1 28 9223
>> 16 1 29 9298
>> 16 1 30 9327
>> 16 1 31 9365
>>
>> Now, I wish to include time (hour) in my data. The new data is of the
>> form:
>> 05 01 06 14    3849
>> 05 01 06 15    3845
>> 05 01 06 16    3836
>> 05 01 06 17    3847
>> 05 01 06 18    3850
>> 05 01 06 19    3872
>> 05 01 06 20    3849
>> 05 01 06 21    3860
>> 05 01 06 22    3868
>> 05 01 06 23    3853
>> 05 01 07 00    3839
>> 05 01 07 01    3842
>> 05 01 07 02    3843
>> 05 01 07 03    3865
>> 05 01 07 04    3879
>> 05 01 07 05    3876
>> 05 01 07 06    3867
>> 05 01 07 07    3887
>>
>> I now read the data as:
>> data <- read.table("data.txt", col.names = c("year", "month", "day",
>> "counts", "hour")) and also included hour in data$date <-
>> as.Date(ISOdate(data$year, data$month, data$day))
>> i.e data$date <- as.Date(ISOdate(data$year, data$month, data$day,
>> data$hour)).
>>
>> However, these did not work.
>>
>> Can you please assist be on how to get this date and time in the right
>> format. The right format I got without hour looks like : 2005-12-29"
>> "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29"
>> [8696] "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29"
>> [8701] "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29"
>> [8706] "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29" "2005-12-29"
>>
>> I used this in my plot. Please I want this format to include hour.
>>
>> Many thanks for your help. I am just a newbe. I am not sure if this
>> forum is the right one. After registration, I tried to post to Nabble
>> forum where I registered but could not succeed.
>>
>> If there is a mistake, please help/direct me to the right forum.
>>
>> Best regards
>> Ogbos
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
>
>