Analyzing time data as POSIXct without dates is IMO unwise (likely to give you
trouble). My approach is to always keep the date and time together or to use
numeric hours-after-midnight. Others have invented packages like chron to deal
with such data.
--
Sent from my phone. Please excuse my brevity.
On March 28, 2017 8:28:30 AM PDT, Troels Ring <tr...@gvdnet.dk> wrote:
>Dear friends - I have a series of times on successive days and would
>like to convert them into a successive common time for each person (ID)
>
>. Using lubridate and adding days(1) does as expected apart from
>changing time zone to LMT from UTC and suddenly adding 9:21 (H:M) to
>all
>times. Individual parts of the instructions seem OK. I'm sorry for the
>clumsy demonstration - but the error comes through.
>
>R version 3.3.2 (2016-10-31) - Windows.
>
>All best wishes
>Troels
>
>library(lubridate)
>
>SSS <- structure(list(ID = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
>1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L,
>3L, 3L, 3L, 3L, 3L, 3L), Time = c(-1L, 0L, 1L, 2L, 3L, 4L, 5L,
>6L, 7L, 8L, 9L, 10L, 11L, -1L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L,
>8L, 9L, 10L, -1L, 0L, 1L, 2L, 3L, 4L, 5L), VT = structure(c(3L,
>5L, 11L, 11L, 8L, 10L, 8L, 10L, 8L, 7L, 11L, 5L, 5L, 12L, 5L,
>7L, 7L, 5L, 5L, 8L, 10L, 8L, 7L, 7L, 7L, 2L, 8L, 7L, 8L, 7L,
>10L, 8L), .Label = c("02:00", "03:00", "04:00", "05:00", "06:00",
>"09:00", "10:00", "11:00", "11:30", "12:00", "13:00", "14:00",
>"15:00", "17:00", "18:00", "21:30", "23:00"), class = "factor")),
>.Names
>= c("ID",
>"Time", "VT"), row.names = c(NA, 32L), class = "data.frame")
>
>SSS$VT <- parse_date_time(SSS$VT,"HM")
>str(SSS$VT)
>
>TT <- list()
>for(i in 1:3) {
>#i <- 1
>BS <- subset(SSS,ID==i)
>TT[[i]] <- c(BS$VT + (1:length(BS[,1])-1)*days(1))
>}
>BS$VT
>(1:length(BS[,1])-1)*days(1)
>
>#these appear as expected but
>
>TT
>
>#appears disturbed 9:21 inserted - LMT time zone - how comes?
>
>______________________________________________
>R-help@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.
______________________________________________
R-help@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.
