> # can use sprintf to convert to a number with 2 digit fractions
> x <- c(10.30, 11, 11.01, 11.09, 11.15, 11.59, 12, 13)
> as.POSIXct(sprintf("%.2f", x), format = "%H.%M")
[1] "2013-01-01 10:30:00 EST" "2013-01-01 11:00:00 EST" "2013-01-01
11:01:00 EST"
[4] "2013-01-01 11:09:00 EST" "2013-01-01 11:15:00 EST" "2013-01-01
11:59:00 EST"
[7] "2013-01-01 12:00:00 EST" "2013-01-01 13:00:00 EST"
>On Tue, Jan 1, 2013 at 11:09 AM, arun <smartpink...@yahoo.com> wrote: > HI, > > Just by taking David's solution: > y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M") > y1<-data.frame(y,AM_PM=format(y,format="%p")) > y1[3,1]-y1[4,1] > #Time difference of -40 mins > y1[5,1]-y1[3,1] > #Time difference of -13 mins > head(y1,2) > # y AM_PM > #1 2013-01-01 11:00:00 AM > #2 2013-01-01 11:15:00 AM > A.K. > > > > > > ----- Original Message ----- > From: Christofer Bogaso <bogaso.christo...@gmail.com> > To: David Winsemius <dwinsem...@comcast.net>; David L Carlson > <dcarl...@tamu.edu> > Cc: r-help@r-project.org > Sent: Tuesday, January 1, 2013 12:40 AM > Subject: Re: [R] Question on creating Date variable > > On 01 January 2013 03:00:18, David Winsemius wrote: >> >> On Dec 31, 2012, at 11:57 AM, David Winsemius wrote: >> >>> >>> On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote: >>> >>>> On 01 January 2013 01:29:53, David Winsemius wrote: >>>>> >>>>> On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote: >>>>> >>>>>> On 01 January 2013 00:17:50, David Winsemius wrote: >>>>>>> >>>>>>> On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote: >>>>>>> >>>>>>>> Hello all, >>>>>>>> >>>>>>>> Let say I have following (numeric) vector: >>>>>>>> >>>>>>>> > x >>>>>>>> [1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14 >>>>>>>> 14.50 >>>>>>>> 14.75 14.85 15.51 14.64 >>>>>>>> >>>>>>>> Now, I want to create a 'Date' variable (i.e. I should be able >>>>>>>> to do >>>>>>>> all calculations pertaining to date/time and also time-series >>>>>>>> plotting etc.) like >>>>>>>> >>>>>>>> 2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31 11:35:00 >>>>>>>> AM, 2012-12-31 12:01:00 PM, . . . . >>>>>>>> >>>>>>> >>>>>>> Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format, >>>>>>> given the number of items to the right of the decimal point that are >>>>>>> greater than 60. So will proceed on the arguably more likely >>>>>>> assumption that they are in fractional minutes. To recover from that >>>>>>> problem, one might consider: >>>>>>> >>>>>>> > as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), >>>>>>> format="%M %S") >>>>>>> [1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST" >>>>>>> [3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST" >>>>>>> [5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST" >>>>>>> [7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST" >>>>>>> [9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST" >>>>>>> [11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST" >>>>>>> [13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST" >>>>>>> [15] "2012-12-31 00:14:38 PST" >>>>>>> >>>>>> >>>>>> I understand that some of those elements are not "dates". However >>>>>> what I want is the ***"PM/AM" suffix*** on those elements which are >>>>>> considered as Dates. >>>>>> >>>>>> ***Getting those suffix*** and doing calculations on those changed >>>>>> variables is my primary concern. >>>>> >>>>> That's the first time that AM/PM has bee mentioned and I suppose if >>>>> those were fractional hours rather than my guess of fractional minutes >>>>> that there might be representatives of both in the numeric data you >>>>> offered. Why don't you clarify what these number do in fact represent? >>>>> And what problem you are trying to solve? >>>>> >>>> >>>> Basically those are artificial data! Actually I do not have the >>>> right to give out the original data in any public forum. So I >>>> created those artificial data so that I can get the fundamental idea >>>> ........... >>>> >>>> Each element (assuming they are legitimate time) represents the time >>>> for a particular day when some event is pop-up. like, 11AM, 11.30AM, >>>> 12.05PM etc.. I could work with something like 11.00, 11.30, 12.05, >>>> 15.00 etc. however I believe adding AM/PM suffice will make my >>>> report more eye-catching. >>>> >>>> Please let me know if you need more clarification. >>> >>> So what's with the values above 59 in the minutes? >> >> Failing an answer to that question, this code shows how to input >> date-time vectors from character vectors and then output it from >> date-time class to character class: >> >> x <- scan(text="11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 >> 13.14 14.50 14.75 14.85 15.51 14.64") # This will come in as a >> numeric vector >> >> ?strptime # for the available format specifications >> format( as.POSIXct(as.character(x), format="%H.%M"), # That is the >> input format >> format="%I.%M %p") # the output format >> [1] NA "11.25 AM" "11.35 AM" "12.01 PM" "11.14 AM" NA >> [7] "01.25 PM" "01.35 PM" "02.01 PM" "01.14 PM" "02.05 PM" NA >> [13] NA "03.51 PM" NA >> >> I suspect that the NA when minutes are ".00" comes from the implicit >> loss of the trailing digits: >> >> > as.character(0.00) >> [1] "0" >> >> The claim that this data is proprietary and cannot presented in its >> original form sound somewhat ridiculous. Simmply post: >> >> dput(head(dfrm$time_data_column_name, 20)) >> >> How could that represent any disclosure of proprietary information if >> presented with no context? >> > > 'How could that represent any disclosure of proprietary information if > presented with no context? ' I must agree with you. But I just dont > want to take any risk! (job scenario in my country is not very > optimistic and I want to give my boss minimal chance/reason to fire!) > > And secondly with your approach, I cant do any calculation. Let take > following example: > > y <- format( as.POSIXct(as.character(x), format="%H.%M"), # That is > the input format > format="%I.%M %p") > > y[3] - y[2] > > This gives me following error: > > Error in y[3] - y[2] : non-numeric argument to binary operator > > I am having same error with Devid's approach as well: > >> y <- as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ), format="%H %M") >> z <- format(y, format="%Y-%m-%d %I:%M %p") >> z[2] - z[1] > Error in z[2] - z[1] : non-numeric argument to binary operator. > > Thanks and regards, > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. > > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. -- 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. ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.
