... and in general, you need to specify the time zone to avoid surprises. In many cases this can be as simple as
Sys.setenv(TZ="GMT") but it can be specific to your data set also. On February 2, 2019 7:09:46 AM PST, Duncan Murdoch <murdoch.dun...@gmail.com> wrote: >On 01/02/2019 10:45 p.m., C W wrote: >> Dear R community, >> >> I am working with dates. And I get the following error: >>> strftime(dat[20], format="%H:%M") >> Error in as.POSIXlt.character(as.character(x), ...) : >> character string is not in a standard unambiguous format > >You are using the wrong function: strftime() formats a time object as >a >character string. You want strptime() to convert character (or factor >in your case) to a time object. > >But you need to give the format for the full string, not just the time >at the end. > >If you really were intending to extract times from dat, then you need >both conversions: > > > strftime(strptime(dat, format="%m/%d/%y %H:%M"), format = "%H:%M") > [1] "11:32" "11:42" "12:17" "12:31" "12:50" "14:10" "14:19" "14:59" >"15:57" "16:00" "16:46" "16:51" "17:35" "17:59" "18:17" "19:07" "19:08" >[18] "19:31" "21:21" "06:00" "06:20" "06:37" "06:40" "06:46" "07:20" >"07:47" "07:50" "07:54" "08:11" "08:23" "08:31" "08:33" "08:43" "09:04" >[35] "09:09" "09:30" "09:59" "10:01" "10:03" "10:05" > >Duncan Murdoch > >______________________________________________ >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. -- Sent from my phone. Please excuse my brevity. ______________________________________________ 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.
