similar to: Subset POSIXlt Field

I have a dataframe of animal locations that I need to have in incremental order so that I can calculate the distance traveled between each time step. However, I have identified a few values that don't seem to sort properly. For instance, the last value in the table below should be the first value after sorting, since its time value is '00:01:35'. But, for some reason, it seems to be

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

Dear R users, Given this data: x <- seq(1,100,1) dx <- as.POSIXct(x*900, origin="2007-06-01 00:00:00") dfx <- data.frame(dx) Now to play around for example: subset(dfx, dx > as.POSIXct("2007-06-01 16:00:00")) Ok. Now for some reason I want to extract the datapoints between hours 10:00:00 and 14:00:00, so I thought well: subset(dfx, dx >

Hi, I have a list/data.frame 'pk' of POSIXct dates, and I'd like to extract the hour for each row. I know that if I have an individual POSIXct object, I can extract the hour by converting to a new object with: new.lt <- as.POSIXlt(<single POSIXct object>) new.lt$hour But I can't figure out how to apply this for a list of such dates in a vectorized form. I can write a

I've seen a few threads about this, but none that seem to answer my problem I have a list of .txt files in a directory that I am reading into R and row binding together. I am using the following code to do so: # Directory where files are found my.txt.file.directory <- "C:/Jared/Data/Kenya/Wildebeest/Tracking_Data" names.of.txt.files <-

Hi Joshua, Thank you for minimizing my test case. > > Hope I'm not doing something illegal... > > > You are. You're changing the internal structure of a POSIXlt object > by re-ordering the list elements. You should not expect a malformed > POSIXlt object to behave as if it's correctly formed. You can see > it's malformed by comparing it's

>>>>> Joshua Ulrich <josh.m.ulrich at gmail.com> >>>>> on Tue, 6 Dec 2016 09:51:16 -0600 writes: > On Tue, Dec 6, 2016 at 6:37 AM, <frederik at ofb.net> wrote: >> Hi all, >> >> I ran into a segfault while playing with dates. >> >> $ R --no-init-file >> ... >> >

Apparently, as.POSIXlt takes one o'clock as the start of the day : > as.POSIXlt(0,origin="1970-01-01") [1] "1970-01-01 01:00:00 CET" > as.POSIXlt(0,origin="1970-01-01 00:00:00") [1] "1970-01-01 01:00:00 CET" > as.POSIXlt(0,origin="1970-01-01 23:59:59") [1] "1970-01-02 00:59:59 CET" Cheers -- Joris Meys Statistical

I have a data frame that contains dates, but when I use as.POSIXlt() I lose the hours on all records. I traced this down to a particuar hour which causes the issue... > as.POSIXlt('2004-10-31 02:00:00') [1] "2004-10-31" > as.POSIXlt('2004-10-31 03:00:00') [1] "2004-10-31 03:00:00" How do I tell as.POSIXlt() to ignore daylight savings and just convert to

Hi, I am encountering a strange error in POSIXlt... anyone got a clue? > as.POSIXlt("1982-01-01") Error in as.POSIXlt.character("1982-01-01") : character string is not in a standard unambiguous format > as.POSIXlt("1992-01-01") [1] "1992-01-01" > as.POSIXlt("1972-01-01") [1] "1972-01-01" > as.POSIXlt("1962-01-01")

Hi, I'm encountering a strange error in POSIXlt... anyone got a clue on this? > as.POSIXlt("1982-01-01") Error in as.POSIXlt.character("1982-01-01") : character string is not in a standard unambiguous format > as.POSIXlt("1992-01-01") [1] "1992-01-01" > as.POSIXlt("1972-01-01") [1] "1972-01-01" >

Hi Guys, I'm cooking up my time series code. I want a data frame with first column as timestamp in POSIXlt format. I hit on this the problem of how to create an array/list/vector of POSIXlt objects. Code is as follows > dtt=array(dim = 2) > t=as.POSIXlt( strptime("07/12/07 13:20:01", "%m/%d/%Y %H:%M:%S",tz="GMT")) > dtt [1] NA NA > t [1]

How can I extract only the time component from an POSIXlt object? For example if I try the following it still returns both the date and time... >as.POSIXlt(tr.date[1]) [1] "2010-10-18 21:46:53" >as.POSIXlt(tr.date[1],"%H:%M:%S") [1] "2010-10-18 21:46:53" round and trunc don't help... is there an "as.Time" equivalent to as.Date ? Thanks,

The length() of a POSIXlt object is given as 9 regardless of the actual length. For example: > make.date.time function (year=c(2006,2006),month=c(8,8),day=2:5,hour=13,minute=45) {# convert year, etc., into POSIXlt object # d=as.character(make.date(year,month,day)) t=paste(hour,minute,sep=":") as.POSIXlt(paste(d,t)) } > t=make.date.time() > t [1] "2006-08-02 13:45:00"

Hi All, I found a possible unexpected behavior when performing match/%in% on POSIXlt objects, e.g. : d <- as.POSIXlt('2018-01-01') # match(<anything>,<POSIXlt>) --> segfault match(0,d) # consequently also this fails : 0 %in% d REPORTED ERROR ON LINUX: *** caught segfault *** address 0x16dc2, cause 'memory not mapped' Verified on 3.5.0 on linux,

Dear list, When using as.POSIXlt with times measured down to microseconds the default format.POSIXlt seems to cause some possibly undesirable behaviour: According to the code in format.POSIXlt the maximum accuracy of printing fractional seconds is 1 microsecond, but if I do; options( digits.secs = 6 ) as.POSIXlt( 1.000002 , tz="", origin="1970-01-01") as.POSIXlt( 1.999998 ,

Hi all, following sample code illustrates the problem : Date1 <- Date2 <- as.POSIXlt(seq.Date(as.Date("2010-04-01"),as.Date("2011-04-01"),by='day')) identical(Date1,Date2) all.equal(Date1,Date2) identical() gives the correct answer. As there is no all.equal method for POSIXlt objects, all.equal.list is used instead. Subsetting using [[]] doesn't work

Hi, I'm having trouble understanding how trunc is operating on vectors of POSIXlt objects. Why does dates[1:4] in the last line return a bunch of NAs even though dates look like it has all the right elements? This worries me that something is off with my use of trunc. Is trunc not suppose to be vectorized with POSIXlt? If not, then how should I truncate a bunch of POSIXlt objects? I'm

Full_Name: Aziz Chaouch Version: 2.2.1 OS: XP/2000 Submission from: (NULL) (132.156.89.240) Hi, I'm not sure this is a "bug" but here is the problem: I'm using the function as.POSIXlt to convert character strings into time objects. I'm using date format as "YYYY/M/D HH:MM" such as as.POSIXlt("1999/6/7 13:30"). Most of the time, this works fine. However

Full_Name: Erich Neuwirth Version: 2.3.1 OS: Windows XP, Linux Submission from: (NULL) (131.130.135.167) Converting Sys.Date() to a POSIX compliant time type in different ways produces inconsistent results: > Sys.date() [1] "2006-09-01" > as.POSIXct(Sys.Date()) [1] "2006-09-01 02:00:00 CEST" > as.POSIXlt(Sys.Date()) [1] "2006-09-01" >