similar to: Class for time of day?

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:

This is mostly a RFC [but *not* about the many extra packages, please..]: Noticing to my chagrin how my students work in a project, googling for R code and cut'n'pasting stuff together, accumulating this and that package on the way all just for simple daily time series (though with partly missing parts), using chron, zoo, lubridate, ... all for things that are very easy in base R *IF*

The documentation for is.atomic and is.recursive is inconsistent with their behavior in R 2.9.1 Windows. ? is.atomic ???? 'is.atomic' returns 'TRUE' if 'x' is an atomic vector (or 'NULL') ???? and 'FALSE' otherwise. ???? ... ???? 'is.atomic' is true for the atomic vector types ('"logical"', ???? '"integer"',

Tested in: R version 2.8.1 (2008-12-22) / Windows Recursive default argument references normally give nice clear errors. In the first set of examples, you get the error: Error in ... : promise already under evaluation: recursive default argument reference or earlier problems? (function(a = a) a ) () (function(a = a) c(a) ) () (function(a = a) a[1] ) () (function(a = a)

Is there a pretty-printer for R data (and code for that matter), similar to Lisp's prettyprint/grind? I've looked in CRAN, and couldn't find anything. For example, I'd like to have: prettyprint(list(a=1:20*2, b=list(data.frame(q = c(2,1,3), r = c(3,1,2), s = c(1,3,2)), as.POSIXct("2014-02-03"))) * =>* list(a = c(2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22,

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, In short, I would like to know if there is any way to convert a numeric into a date, similar to how strptime() can convert a string to a date time class? There are some functions, etc. which don't work well with dates, and tend to force them into numerics. I understand that the number it spits back is the number of seconds since the beginning of 1970 (see the first few sentences

Dear all, I have a variable 'x' like that: > x [1] "2005-09-01" Here, 2005 represents year, 09 month and 01 day. Now I want to create three variables naming: y, m, and d such that: y = 2005 m = 09 d = 01 can anyone tell me how to do that? Regards, [[alternative HTML version deleted]]

I have a frame which contains 3 columns: "date" "defectnum" "state" And I want to get the most recent state change for a given defect number. date is POSIXct. I have tried: aggregate(ev$date, by=list(ev$defectnum), max) Which appears to be working except that the dates seem to come back as integers (presumably the internal representation of POSIXct). When I

I have two vectors, a and b. b is a text file. I want to find in b those elements of a which occur at the beginning of the line in b. I have the following code, but it only returns a value for the first value in a, but I want both. Any ideas please. a = c(2,3) b = NULL b[1] = "aaa 2 aaa" b[2] = "2 aaa" b[3] = "3 aaa" b[4] = "aaa 3 aaa"

Inspired by the exchange between Rolf Turner and Wacek Kusnierczyk, I thought I'd clear up for myself the exact relationship among the various sequence concepts in R, including not only generic vectors (lists) and atomic vectors, but also pairlists, factor sequences, date/time sequences, and difftime sequences. I tabulated type of sequence vs. property to see if I could make sense of all

Inspired by the exchange between Rolf Turner and Wacek Kusnierczyk, I thought I'd clear up for myself the exact relationship among the various sequence concepts in R, including not only generic vectors (lists) and atomic vectors, but also pairlists, factor sequences, date/time sequences, and difftime sequences. I tabulated type of sequence vs. property to see if I could make sense of all

In R 2.9.1 Windows: > nchar(factor(paste('sdf',1:10))) [1] 1 1 1 1 1 1 1 1 2 1 so it appears that nchar is counting the number of characters in the numeric representation, just like: > nchar(as.numeric(factor(paste('sdf',1:10)))) [1] 1 1 1 1 1 1 1 1 2 1 but ?nchar says explicitly: x: character vector, or a vector to be coerced to a character vector.

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.

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 =

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",

I recently traced a bug of mine to the fact that cumsum(s)[length(s)] is not always exactly equal to sum(s). For example, x<-1/(12:14) sum(x) - cumsum(x)[3] => 2.8e-17 Floating-point addition is of course not exact, and in particular is not associative, so there are various possible reasons for this. Perhaps sum uses clever summing tricks to get more accurate results? In some

Dear R list, I noticed the following 'problem' when changing the format of dates created with seq.dates() (from the Chron library) using as.POSIXct() (R 1.8.0 on OSX 10.2.8): > datesTest<-seq.dates(from="10/01/1952", length=3, by="days"); > datesTest [1] 10/01/52 10/02/52 10/03/52 # Now changing the format to show year as 1952. >

> (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