yes jim, that's pretty close to what I managed to do after your first hint
###
mys.100<-sprintf(".%02d", df$s.100)
myhour<-strftime(df$hour, format = "%H:%M:%S")
myday<-strftime(df$date, format = "%Y-%m-%d")
my.new.datetime<-as.POSIXct(paste0(paste(myday, myhour),mys.100))
op <- options(digits.secs = 2)
my.new.datetime
###
thank you again for the help
best regards
Il 29/04/2014 23:02, jim holtman ha scritto:
> Here is how I would do the conversion. I start off by setting my
> timezone to GMT.
> #############################
> > df<-structure(list(date = structure(c(1395874800, 1395874800,
> + 1395874800,
> + 1395874800, 1395874800), class = c("POSIXct", "POSIXt"), tzone = ""),
> + hour = structure(c(-2209121804, -2209121567, -2209121005,
> + -2209118616, -2209116160), class = c("POSIXct", "POSIXt"),
> tzone =""),
> + s.100 = c(29L, 36L, 6L, 53L, 18L)), .Names = c("date", "hour",
> + "s.100"), row.names = c(NA, -5L), class = "data.frame")
> >
> > # setup GMT as my timezone
> > Sys.setenv(tz = "GMT")
> > df
> date hour s.100
> 1 2014-03-26 23:00:00 1899-12-30 11:03:16 29
> 2 2014-03-26 23:00:00 1899-12-30 11:07:13 36
> 3 2014-03-26 23:00:00 1899-12-30 11:16:35 6
> 4 2014-03-26 23:00:00 1899-12-30 11:56:24 53
> 5 2014-03-26 23:00:00 1899-12-30 12:37:20 18
> > # show numeric value of midnight on 2014-03-27 and compare to table
> > as.numeric(as.POSIXct('2014-03-27 00:00', tz = "GMT"))
> [1] 1395878400
> > as.numeric(df$date[1])
> [1] 1395874800
> > # shows your time is off by an hour so we have to add back
> > # create the date format to convert
> > newDate <- paste0(format(df$date + 3600, format = "%Y-%m-%d")
> + , ' ' # blank separator
> + , format(df$hour + 3600, format = "%H:%M:%S")
> + , sprintf(".%02d", df$s.100)
> + )
> > # result, and now convert back into a new column
> > newDate
> [1] "2014-03-27 12:03:16.29" "2014-03-27 12:07:13.36" "2014-03-27
> 12:16:35.06" "2014-03-27 12:56:24.53"
> [5] "2014-03-27 13:37:20.18"
> > df$time <- as.POSIXct(newDate, format = "%Y-%m-%d %H:%M:%OS", tz =
> "GMT")
> > df
> date hour s.100 time
> 1 2014-03-26 23:00:00 1899-12-30 11:03:16 29 2014-03-27 12:03:16
> 2 2014-03-26 23:00:00 1899-12-30 11:07:13 36 2014-03-27 12:07:13
> 3 2014-03-26 23:00:00 1899-12-30 11:16:35 6 2014-03-27 12:16:35
> 4 2014-03-26 23:00:00 1899-12-30 11:56:24 53 2014-03-27 12:56:24
> 5 2014-03-26 23:00:00 1899-12-30 12:37:20 18 2014-03-27 13:37:20
>
> > # the time does have the hundredth of the second
> > format(df$time, format = "%H:%M:%OS2")
> [1] "12:03:16.28" "12:07:13.35" "12:16:35.05" "12:56:24.52" "13:37:20.18"
> >
> ############################################
>
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
>
>
> On Tue, Apr 29, 2014 at 3:15 PM, <mbres...@arpa.veneto.it
> <mailto:mbres...@arpa.veneto.it>> wrote:
>
> hi, thanks for your reply
>
> the first record for my date is 2014-03-27 and for my hour is
> 1899-12-30
> 12:03:16
>
> I got to this point by importing some data via RODBC from an
> access database
>
> Now, I would like to get a single column with the date and the
> time that
> for the first record should be equal to:
>
> 2014-03-27 12:03:16.029
>
> and this result should be the combination of relevant information
> contained in the 3 columns: "date", "hour" and "s.100"
>
> I do not have the possibility to change the format of imported
> data so I
> need necessarly to convert them later on...
>
> how would you do that considering that regardless of the time zone
> displacement the first column is storing the data, the second the
> hour and
> the third the hundredth of a second
>
>
> best regards
>
> > When I read in your data, I get the following since I am in the
> EDT time
> > zone:
> >
> >> df<-structure(list(date = structure(c(1395874800, 1395874800,
> >> 1395874800,
> > + 1395874800, 1395874800), class = c("POSIXct", "POSIXt"), tzone
> = ""),
> > + hour = structure(c(-2209121804, -2209121567, -2209121005,
> > + -2209118616, -2209116160), class = c("POSIXct",
> "POSIXt"), tzone =
> > ""),
> > + s.100 = c(29L, 36L, 6L, 53L, 18L)), .Names = c("date",
> "hour",
> > + "s.100"), row.names = c(NA, -5L), class = "data.frame")
> >>
> >> df
> > date hour s.100
> > 1 2014-03-26 19:00:00 1899-12-30 06:03:16 29
> > 2 2014-03-26 19:00:00 1899-12-30 06:07:13 36
> > 3 2014-03-26 19:00:00 1899-12-30 06:16:35 6
> > 4 2014-03-26 19:00:00 1899-12-30 06:56:24 53
> > 5 2014-03-26 19:00:00 1899-12-30 07:37:20 18
> >
> >
> > I assume your real date is probably 2014-03-27 if it supposed to
> be GMT.
> > And your 'hour' is funny for probably the same reason. You can
> easily
> > convert the hundredth of a second in the original input.
> >
> > Now I would really like to ask how you got to this point. Did you
> > originally read in and convert the data yourself, or is this a
> source that
> > you do not have any control over? If the former, then just use the
> > correct
> > conversion. As shown below, if you have hundredths of a second,
> that will
> > be converted correctly and you don't need the extra column.
> >
> >> x <- as.POSIXct("2014-04-29 12:00:00.345") # decimal seconds
> that are
> > converted
> >>
> >> x
> > [1] "2014-04-29 12:00:00 EDT"
> >> format(x, format = "%H:%M:%OS3") # print with 3 decimals
> > [1] "12:00:00.345"
> >
> > If you have the choice, start over again and do it correctly.
> If not,
> > convert the various components to the correct character format
> for your
> > timezone, combine back together and then use the conversion
> shown above.
> >
> >
> > Jim Holtman
> > Data Munger Guru
> >
> > What is the problem that you are trying to solve?
> > Tell me what you want to do, not how you want to do it.
> >
> >
> > On Tue, Apr 29, 2014 at 9:06 AM, Massimo Bressan
> > <mbres...@arpa.veneto.it <mailto:mbres...@arpa.veneto.it>>wrote:
> >
> >> I have this dataframe:
> >>
> >> df<-structure(list(date = structure(c(1395874800, 1395874800,
> >> 1395874800,
> >> 1395874800, 1395874800), class = c("POSIXct", "POSIXt"), tzone
> = ""),
> >> hour = structure(c(-2209121804, -2209121567, -2209121005,
> >> -2209118616, -2209116160), class = c("POSIXct", "POSIXt"),
> tzone =
> >> ""),
> >> s.100 = c(29L, 36L, 6L, 53L, 18L)), .Names = c("date", "hour",
> >> "s.100"), row.names = c(NA, -5L), class = "data.frame")
> >>
> >>
> >> and I would like to sum first two columns ("date" and "hour")
> so that to
> >> end up with a new column, say "date_hour", storing both the
> information
> >> about the "date" and the "hour" in one POSIXct object;
> >>
> >> I have been reading that POSIXct objects are a measure of
> seconds from a
> >> given origin (1st Jan 1970), so that a possible solution is to
> tranform
> >> the
> >> column "hour" into seconds and then add it to the column "date";
> >>
> >> but, is there a staightforward solution for accomplishing this
> task?
> >> I've been trying to extract from the column "hour" the digits
> >> representing
> >> hours, minutes and seconds and transform everything into
> seconds but
> >> that
> >> seem to me quite cumbersome approach...
> >>
> >> and finally, one more question: is it possible to represent
> hundred of
> >> seconds as given in the column "s.100" of the given dataframe
> within the
> >> same new POSIXct object "date_hour"?
> >>
> >>
> >> thanksfor the support
> >>
> >>
> >>
> >>
> >> [[alternative HTML version deleted]]
> >>
> >> ______________________________________________
> >> R-help@r-project.org <mailto:R-help@r-project.org> mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-help
> >> PLEASE do read the posting guide
> >> http://www.R-project.org/posting-guide.html
> <http://www.r-project.org/posting-guide.html>
> >> and provide commented, minimal, self-contained, reproducible code.
> >>
> >
>
>
>
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