[R] as.Date

PIKAL Petr petr.pikal at precheza.cz
Mon Apr 18 16:01:28 CEST 2016


Hi

AFAIK as.Date does not accept hours. Although it is not explicitly written in help page, the name as.Date seems to me clear enough that it works only with dates.

If you want to use hours, minutes ... you should use strptime for converting your values to valid date_time object.

And you should also use ISOdatetime conversion function to use hours etc. in your commands.

Cheers
Petr


> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ogbos
> Okike
> Sent: Monday, April 18, 2016 3:10 PM
> To: r-help at r-project.org
> Subject: [R] as.Date
>
> 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.

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