Displaying 20 results from an estimated 10000 matches similar to: "Daylight Savings Time unknown in R-2.2.1"
2006 Oct 27
2
POSIXct time zone and daylight savings issues
Hello,
Suppose we need a function that takes a POSIXct object and need to
calculate the time difference between it and GMT time:
gmtDiff <- function(time) {
time.gmt <- as.POSIXct(format(time, tz="GMT"))
time.plt <- as.POSIXlt(time)
dlstime <- ifelse(time.plt$isdst > 0, 1, 0)
timezone <- as.numeric(difftime(time, time.gmt, units="hours"))
2012 Sep 05
2
POSIXlt and daylight savings time
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
2012 Jul 02
1
Undocumented behavior around daylight savings time?
Apologies for the intrusion. I am a lurker on list.
I have been working to convert a digitized signal from a matlab file into R
for analysis and other applications. R.matlab is working fine, and it is
easy to convert the matlab date-time number (days since year 0) into R
date-time numbers (seconds since 1970-01-01).
Unfortunately, when I cast the R date-time number into POSIXct format it
seems
2011 Jun 22
2
strange date problem - May 3, 1992 is NA
> is.na(strptime("5/2/1992", format="%m/%d/%Y"))
[1] FALSE
> is.na(strptime("5/3/1992", format="%m/%d/%Y"))
[1] TRUE
Any idea what's going on with this? Running strptime against all dates
from around 1946, only 5/3/1992 was converted as "NA". Even stranger,
it still seems to have a value associated with it (even though is.na
thinks
2008 Mar 05
3
types of vectors / lists
Hello,
I am an advanced user of R. Recently I found out that apparently I do
not fully understand vectors and lists fully
Take this code snippet:
T = c("02.03.2008 12:23", "03.03.2008 05:54")
Times = strptime(T, "%d.%m.%Y %H:%M")
Times # OK
class(Times) # OK
is.list(Times) # sort of understand and not understand that
length(Times)
2002 May 03
1
Daylight savings time and conversion to POSIXt (arghh!)
I have asked this question before, and received some suggestions for
work-arounds that get the job done--and they are much appreciated.
But I would still like to find out if I'm missing something, and
whether there is a direct way using POSIXt functions (as.POSIXct,
as.POSIXlt, strptime, in particular).
I have environmental data collected once per minute. Here is a subset
of 3 input
2008 Mar 31
3
UK Daylight Savings
A quick fix for anyone running into this problem:
load_schedule was crashing cron_trigger.rb#160, and I found that for
triggers like "0 20 5 * * * *" it was putting in 32 for the date (even
though its Mon Mar 31 04:16:21 BST 2008). Something to do with switching to
day light savings I think, which concludes after 2am. I patched it by adding
day = 31 if day == 32
on the line before.
2002 May 12
0
{round,trunc}.POSIXt and daylight savings time (PR#1543)
I have found what looks like a small problem in trunc.POSIXt()
involving the transition to/from standard time and daylight savings
time. Assuming my assessment is correct, I have a potential solution
to offer.
If a time in daylight savings time is rounded such that the rounded
value is on the other side of the transition, the isdst element does
not get changed accordingly. I have tested only
2011 Mar 10
1
Timezone issue with strftime/strptime and %z and %Z
Hello!
I've been trying to get this right for quite a while now and fear
there is an easy solution I just don't see. I did not have this
problem in Linux, and I searched r-help and Google but did not find a
solution, but of course I am grateful for and resources I might not
have found our not understood yet.
I try to parse a time stamp with time zone. I essentially just want to
parse the
2010 Oct 01
3
Converting a dataframe column from string to datetime
Hi,
I have a dataframe column of the form
v<-c("Fri Feb 05 20:00:01.43000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:06.34000 2010")
I need to convert this to datetime form. I did the following..
lapply(v,function(x){strptime(x, "%a %b %d %H:%M:%OS %Y")})
This gives me a list that looks like
2016 Apr 04
2
Understanding POSIXct creation on different OSes.
Hello,
Following Dirk's post here: https://github.com/Rdatatable/data.table/issues/1619
we would like to clarify if this is the right behaviour, and if so,
the rationale behind it.
Here's the summary (thanks to Dirk and Joshua):
Sys.setenv("TZ"="America/Chicago")
dates = as.Date("2016-03-02") + (0:3)*7 # four Wednesdays
# [1] "2016-03-02"
2003 Aug 13
1
Problems with addition in big POSIX dates
Have you noticed any problems with big dates (>=1/1/2040) in R?
Here is the bit of code that I'm having trouble with:
> test.date <- strptime("1/1/2040",format="%m/%d/%Y")
>
> unlist(test.date)
sec min hour mday mon year wday yday isdst
0 0 0 1 0 140 0 0 0
>
> date.plus.one <- as.POSIXct(test.date) +
2008 Apr 10
1
ISOdate/ISOdatetime performance suggestions, other date/time questions
Dear list:
working with date/times I have come across a problem that ISOdate and
ISOdatetime are too slow on large vectors of data. I was surprised just
until I looked at the implementation and the man page: "ISOdatetime and
ISOdate are convenience wrappers for strptime". In other terms, they
convert data to character representation first in order to create a
POSIXlt object that is then
2010 Feb 01
1
Error with cut.POSIXt and daylight savings time switchover dates
The following code:
cut(as.POSIXct("2009-11-01 04:00:00", tz="America/Los_Angeles"), "1 day")
gives the error:
Error in seq.int(0, to - from, by) : 'to' must be finite
This is related to November 1st, 2009 being the switchover date from daylight savings time to standard time in the America/Los_Angeles time zone. In particular, in cut.POSIXt, the starting
2003 Jan 03
4
as.POSIXct problem?
Under
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system i686, linux-gnu
status
major 1
minor 6.1
year 2002
month 11
day 01
language R
> x <- strptime(c('10/10/1969','12/31/2002'),format='%m/%d/%Y')
2008 Feb 17
1
How to make a vector/list/array of POSIXlt object?
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]
2014 Jun 03
3
error de incompatible methods
Hola!!
Estoy intentando ejecutar un script com horas, al principio ejecute estos
comandos
DBx$Date<-strptime(DBx$Date, "%d-%m-%Y") ###Monicap use ; other
use Y
DBx$Year<-as.POSIXlt(DBx$Date)$year+1900
if(filename!="monicap_50.csv") {DBx$Time<-paste(DBx$Time, ":00", sep="")}
Pero me daba el error de que mi base de datos tenia las
2002 Oct 17
4
Posix Problem, difftime
I am having a series of problems using date time data that has been converted into a POSIXt and POSIXlt classes. I have hourly time series data from 1900 that has been converted from text data.
I assume most of my problems come from a mis-underdanding of the POSIX class. My matrix named (aa) for this year is approx 8700 by 4. When I try to calculate the length of posit column ( which is the
2002 Apr 11
6
extract week from date
Hello R-users,
Does anyone know how obtain the week of a date?
(in SPPS the instruction is "xdate.week")
Thanks,
Juan Ramon
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2020 Oct 23
2
The presence/absence of `zone` in POSIXlt depending on time zone as a cause of possible inconsistences?
Dear all,
I have just detected what seems a minor inconsistence with data types. If one unlists a POSIXlt time with GMT zone gets a numeric vector, since the POSIXlt list has no `zone` element, while if one unlists a POSIXlt time with a non GMT zone (also non specifying tz if the Sys.timezone is not GMT) gets a character vector due to including the `zone` element.
> x <-