[R] as.Date

[Jeff Newmiller]

Date data cannot represent hour data. You need to use POSIXct or perhaps the chron class from the chron package. 

To use POSIXct, use ISOdatetime instead of ISOdate. Also be careful which timezone you have set as default (in most operating systems calling Sys.setenv(TZ="Etc/GMT") or similar will get you started) when you invoke ISOdatetime, since daylight savings can complicate things. Of course if daylight savings is built into your data already then  you are better off choosing a timezone that understands that. See ?DateTimeClasses.
-- 
Sent from my phone. Please excuse my brevity.

On April 18, 2016 6:09:50 AM PDT, 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
>
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