similar to: Doing things with POSIXt

Hi, I have two data sources. One records time in PST time zone, the other in GMT. I want to compute the difference between the two, but don't see how. Here is an example where I compute time difference between identical times each (meant to be) relative to its time zone. > as.POSIXlt("2000-05-10 10:15:00", "PST") - as.POSIXlt("2000-05-10 10:15:00",

Hi all, I need to compare time series data files of different time formats. I had no problems with text format using strptime. But how can I convert datetime numbers from Excel (days since 30.12.1899 00:00:00) into POSIXt objects? For example 29770.375 should be converted to "03.07.1981 09:00:00" I tried the following code and encountered strange results: t1-t0 gives 29770.33

I have a problem ordering by descending magnitude a POSIXt object. Can someone help please and let me know how to work around this. My goal is to be able to order my data by DATE and then by descending TIME. I have tried to include as much info as possible below. The problem stems from trying to read in times from a CSV file. I have converted the character time values to a POSIXt object using the

Hello, ?DateTimeClasses states that "one can add or subtract a number of seconds or a 'difftime' object from a date-time object, but not add two date-time objects." So, is the below expected behavior? > x <- Sys.time() > x [1] "2007-02-21 16:19:56 CST" > x + as.difftime("1","%H") [1] "2007-02-21 16:19:57 CST" Warning

I have a problem with results from difftime being 1 hour different than expected. 2 examples are given below: datetime <- matrix(data=rbind(c("2012-03-31 21:00:00", "2012-04-01 00:00:00", "2012-04-01 03:00:00", "2012-04-01 06:00:00"), c("2012-10-06 21:00:00", "2012-10-07 00:00:00", "2012-10-07 03:00:00",

I am a beginner in R with a background in SAS. Are there built-in R methods of reading dates for calculating elapsed days between two calendar dates? If so, are there any examples I can browse? Thanks in anticipation. John Byrne. Lecturer in Information Systems. Australian Catholic University.

Is there a quick function that can convert minutes (seconds) after midnight to a time? i.e 670.93 (minutes after midnight) --> 11:10:56.** I know it can be done by hand but I thought there must be a function for this already. Thank you. [[alternative HTML version deleted]]

Dear all, according to the Help-page of DateTimeClasses {base} I should be able to do time - z with time date-time objects z a numeric vector (in seconds) or an object of class "difftime". However, on R version 2.6.0 (Windows XP) I get > Sys.time() - as.difftime(c("0:3:20", "11:23:15")) Time differences in mins [1] 1191837998 1191837318

I am trying to extract only the winters (defined to be 01-Dec through 28-Feb) of daily data from 1948-2002. There are 90 days in each winter season. I wrote the following code to gather the winter dates into a single vector: DJF <- NULL for(year in 1949:1999) { temp.begin <- strptime(paste("01/12", year-1, sep="/"), "%d/%m/%Y") temp.end <-

Date-Time-Stamp input method to correctly interpret user-specific formats:coding is 90% there - based on exmple at http://tolstoy.newcastle.edu.au/R/help/05/02/12003.html ...anyone got the last 10% please? CONTEXT: Data is received where one of the columns is a datetimestamp. At midnight, the value represented as text in this column consists of just the date part, e.g.

Hi, Does anybody know why get I this kind of strange situation: Browse[2]> hcEnd [1] "2009-03-29 06:30:00" Browse[2]> class(hcEnd) [1] "POSIXlt" "POSIXt" Browse[2]> is.na(hcEnd) [1] TRUE This issue is the source of my all issues in my program, Thanks for your help -- View this message in context:

I use POSIXct for datetimes. Is thee a timeAlign function that I can use where : align by year direction -1 ==> start of this year direction 1 ==> start of next year align by week direction -1 ==> date on last sunday direction 1 ==> date on next sunday align by day direction -1 ==> time at past midnight direction 1 ==> time at this comming

I want to obtain datetime differences in mins in an other column, in front of my datetimes. I have tried this : T1 <- c("12/31/03 23:49","1/1/04 1:14","1/1/04 0:02") T2 <- c("1/1/04 0:58","1/1/04 1:16","") toto <- data.frame(T1,T2) toto y <- strptime(T1,"%m/%d/%y %H:%M") x <- strptime(T2,"%m/%d/%y

If I take the following simple data: YEAR MONTH DAY WEIGHT.KG 2003 10 6 1.2 2003 10 12 1.2 2003 10 16 1.3 and format the date data and plot it: dates <- strptime(paste(DAY,MONTH,YEAR),"%d%m%Y") plot(c(min(dates),max(dates)),c(0,max(WEIGHT.KG)), xlab="Date",ylab="Weight (kg)",type="n") lines(dates,WEIGHT.KG) points(dates,WEIGHT.KG) I find that the

From: Vitalie S. <vitosmail <at> rambler.ru> Subject: Bug in cut.POSIXt Newsgroups: gmane.comp.lang.r.general Date: 2009-10-15 15:47:48 GMT (1 hour and 29 minutes ago) Hello Everyone, Before reporting decided to post here first: tt <- structure(c(1254238817, 1254238859, 1254238969, 1254239080), class = c("POSIXt",

I just encountered another RTFM problem: With diff(as.POSIXct(...), ...) I was unable to control the units of the results. Examples: > (d.d <- diff(as.POSIXct(c('2012-12-12', '2012-12-13')))) Time difference of 1 days > (d.h <- diff(as.POSIXct(c('2012-12-12 08:00', '2012-12-12 09:00')))) Time difference of 1 hours > (d.m <-

Hello all!!! I want to measure the duration of events (given a start and an end time). The catch is that I require the output in calender days. This means: 02-Jan-2011 00:01:00 minus 01-Jan-2011 23:59:00 should be 1 day (although the real time difference is only 2 minutes) My data is the following head(episode.ct) [1] "2009-07-13 13:37:20 CEST" "2009-07-14 07:29:20 CEST"

Since both comparison and negation are well-defined for time differences, I wonder why abs and division are not defined for class difftime. This behavior is clearly documented on the man page: "limited arithmetic is available on 'difftime' objects"; but why? Both are natural, semantically sound, and useful operations and I see no obvious reason that they should give an error:

Since both comparison and negation are well-defined for time differences, I wonder why abs and division are not defined for class difftime. This behavior is clearly documented on the man page: "limited arithmetic is available on 'difftime' objects"; but why? Both are natural, semantically sound, and useful operations and I see no obvious reason that they should give an error:

I have a time series with interval of 2.5 minutes, or 24 observations per hour. I am trying to find a 1 hr moving average, looking backward, so that moving average at n = mean(n-23 : n) The time series has about 1.5 million rows, with occasional gaps due to poor data quality. I only want to take a 1 hour moving average for those periods that are complete, i.e. have 24 observations in the