similar to: Help useRs to use R's own Time/Date objects more efficiently

I think POSIXct and POSIXlt are badly-chosen names. The name "POSIX" implies UNIX. (i.e. XYZix operating system is mostly POSIX compliant... Woo-Hoo!). My assumption is that most people modelling industrial/econometric data etc, or data imported from databases, don't want system references everywhere. Historically, I've use the principle that: If programming language A uses

I know that this is correct: library(chron) x = dates("01-03-04", format="d-m-y", out.format="day mon year") print(x) It gives me the string "01 Mar 2004" which is correct. I also know that I can say: print(day.of.week(3,1,2004)) in which case he says 1, for today is monday. My question is: How do I combine these two!? :-) I have a

Hi, how it's possible to extract the year and the number of days from Julian date. i'm little confused about the last two functions and ?years . EDATE comes from sqlQuery with as.is=T EDATE <- as.POSIXlt(datvears$ENROLLDAY) Many thanks, Christian > EDATE[1:5] [1] "2000-06-30 11:25:01" "2000-06-30 11:39:55" "2000-06-30 12:11:11" [4]

Can anyone please shed any light on why R DateTimeClasses give weird times for when daylight saving time information changes, and which aren't consistent with the OS? Example: Expected result: in New Zealand DST stopped (NZDT -> NZST) at 03:00 NZDT on 2010-04-04, as confirmed by the OS time zone info (OS X 10.8.2): zdump -v /etc/localtime /etc/localtime Sat Apr 3 13:59:59 2010 UTC

Hello, When following a thread that started today [1], I read the documentation for DateTimeClasses {base} more carefully and noticed a typo in the "Details on POSIXlt" section, in the paragraph right after the components list. The original and corrected are "he" instead of "the". From earlier versions of R, he last two components will not be present for

> (1) Create a top-level help page with a title like "Date and Time > Classes" to give a brief but general overview. This would mean the > existing DateTimeClasses would need a new title. I wanted to modify my first suggestion. Perhaps a better idea would be to reference an external document giving an overview of the subject. I couldn't find a discussion of POSIXct/POSIXlt

Hi list, I'm trying to turn a date into something productive. (Not what you may be thinking....) I want three functions so I could take a "date" object and get the day of week, month, and year from it. xx <- as.Date("2006-01-05") month(xx) equal 1 day(xx) equal 5 year(xx) equal 2006 I'm aware of the weekdays() and months() functions in the base package. But

Hi, I'm trying to aggregate date values using the aggregate function. For example: aggregate(data,by=list(weekdays(LM),months(LM)),FUN=length) I would also like to aggregate by year but there seems to be no years() function. Should there be one? Is there any alternative choice? Also, a hours() function would be great. Any tip on this? Thanks in advance! S?rgio Nunes

Times from seq.POSIXt come out wrong in AEST timezone around Feb 29 every leap year before 1970 (on Windows XP). According to help(DateTimeClasses), this is handled by "our own C code". > x <- as.POSIXct("1968-02-27") # tz="AEST" > x.gmt <- as.POSIXct("1968-02-27", tz="GMT") > data.frame( GMT=seq(x.gmt, by="day",

I would like to use POSIX classes to store dates and extract components of dates. Following the example in Spector ("Data Manipulation in R"), I create a date > mydate = as. POSIXlt('2005-4-19 7:01:00') I then successfully extract the day with the command > mydate$day [1] 19 But when I try to extract the month > mydate$mon [1] 3 it returns the wrong month. And

Hi I need to add an year to and date field in the dataframe. Please help me X Date 1 2008-01-01 2 2008-02-01 3 2003-03-01 Thanks in advance -- View this message in context: http://r.789695.n4.nabble.com/Adding-a-year-to-existing-date-tp4078930p4078930.html Sent from the R help mailing list archive at Nabble.com.

On the documentation page for DateTimeClasses, in the Examples section, there are the following two lines: format(.leap.seconds) # the leap seconds in your time zone print(.leap.seconds, tz = "PST8PDT") # and in Seattle's The second line (using print) seems to ignore the tz argument, and prints the dates in my time zone, while: format(.leap.seconds, tz =

Hi, I'm having a weird result with the length() function: >a [... omited ...] [9994] NA "2003-12-03 16:37:00" "2002-06-26 18:43:00" [9997] "2005-07-04 04:00:00" "2007-02-16 22:09:00" "2007-02-24 15:49:00" [10000] NA > length(LastModified) [1] 9 > length(c(LastModified)) [1] 9 I was expecting to get

R V2.0.1 on Windows XP. I have read the help pages on strptime() over and over, but can't understand why strptime() is producing the following results. > v <- format("2002-11-31", format="%Y-%m-%d") > v [1] "2002-11-31" > factor(v, levels=v) [1] 2002-11-31 Levels: 2002-11-31 > x <- strptime("2002-11-31",

Hallo! I lese gro?e Zeitreihen in R ein z.B. mit: > disc<-read.table("F:/R/DATA/discount_rate_usa.txt") disc hat dann folgende Struktur: > disc[1:5] V1 V2 1 01/03/1955 1.5 2 01/04/1955 1.5 3 01/05/1955 1.5 4 01/06/1955 1.5 5 01/07/1955 1.5 ich will das disc als Zeitreihe erkannt wird und will z.B 01/03/1955 in ein Datum verwandeln, aber es wird als

Hello, I have seen much discussion on Date. But I can't seem to do this simple operation. I can convert a string to a date: d <- as.Date(DATE, format="%m/%d/%Y") But what I want to do is extract the year and month so I can construct an element in a ts object. Ideally I would like to see d$year but that doesn't seem to be available. Once I have a Date object how can I get an

Delving into the murky world of dates and times I found this: dates <- c("02/27/92", "02/27/92", "01/14/92", "02/28/92", "02/01/92") > times <- c("23:03:20", "22:29:56", "01:03:30", "18:21:03", "16:56:26") > x <- paste(dates, times) > z <- strptime(x, "%m/%d/%y

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.

Hello, I'm trying to write a function that returns the number of weekdays between a vector of start dates and a vector of end dates. Subtracting the 2 times the number of whole weeks is the easy part and works if the number of days is a multiple of 7. However, the number of weekend days in the tail is a little harder. It depends on both the start date of the tail and the number of days in

Hi, Given a frame with calendar date's: "2005-07-01", "2005-07-02","2005-07-03","2005-07-04","2005-07-05",etc. I want to extract the following from these dates: week number month number year number Any ideas how to accomplish this? Many thanks. Regards, Richard