similar to: day, month, year functions

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 <-

Dear all, I have a question related to the POSIXlt function in R. I have a set of dates and times, for exmaple: startx <- as.POSIXct("2011-01-01 00:00:00") finx <- as.POSIXct("2011-12-31 00:00:00") daysx<- seq(startx, finx, by="24 hours") I want to change the dates of all the days falling on a Saturday to the next working day (i.e. Monday). So I

Hello, I want to change the day of the month in a date object. What I am doing at the moment is: x=as.POSIXlt(x) x$mday=13 x=as.Date(x) Does anybody know if there is a more "natural" (eficient) way to do this Thank you Felipe Parra [[alternative HTML version deleted]]

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]

I've always found the chron library to be useful for tasks like this: > x <- round(runif(10)*100000, digits=0) > y <- as.Date(x, origin="1970-01-01") > library(chron) > days(y) [1] 7 25 26 25 10 24 1 31 12 8 31 Levels: 1 < 2 < 3 < 4 < 5 < 6 < 7 < 8 < 9 < 10 < 11 < 12 < 13 < ... < 31 Notice that it returns the days as

> x<-as.POSIXct("1970-1-1", tz="UTC")-.5 > y<-as.POSIXct("1970-1-1", tz="UTC")+.5 > x==y [1] FALSE # of course but x and y "appear" to be the same when formatted, even with extra precision: > format(x, format="%Y-%m-%d %H:%M:%OS2") [1] "1970-01-01 00:00:00.50" > format(y, format="%Y-%m-%d

> 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

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')

I have a vector of dates. I wish to find the month end date for each. Any suggestions? e.g. For 12/15/05, I want 12/31/05, For 10/15/1995, I want 10/31/1995, etc __________________________________________________ [[alternative HTML version deleted]]

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]]

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"

hello, I have a vector of factors > str(rcptdt) Factor w/ 51 levels "1/10/03","1/13/03",..: > length(rcptdt) [1] 87 which i want to convert to class POSIXlt to extract the day, so: a1<-format(rcptdt,"%m/%d/%y") > length(a1) [1] 87 and: a2<-strptime(a1, "%m/%d/%y") str(a2) `POSIXlt', format: chr [1:87] "2002-04-18"

Hi, I have some confusion in applying a function over a column. Here's my function. I just need to shift non-March month-ends to March month-ends. Initially I tried seq.dates, but one cannot give a negative increment (decrement) here. return(as.Date(seq.dates(format(xdate,"%m/%d/%Y"),by="months",len=4)[4]) ) Hence this simple function: > mydate <-

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

The interface for dates in R is a little confusing to me. I want to create a vector of Date objects from vectors of years, months, and days. One solution I found is: years <- c(1991, 1992) months <- c(1, 10) days <- c(1, 2) dates <- as.Date(ISOdate(years, months, days)) But, in this solution the ISOdate function converts the vectors into characters, which can cause serious

In the following, can anyone tell me why length(eee) returns 9? I was expecting 15398, and when I try to add this vector to a data frame with that many rows, it fails complaining that the vector is of length 9. In what I thought was an identical situation with a related dataset, the same code worked as expected. > length(fff) [1] 15398 > str(fff) int [1:15398] 20010102 20010102

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:

dear All, i'm trying to calculate the number of Mondays, Tuesdays, etc that each month within a date range has. I have time series data that spans 60 months and i want to calculate the number of Mondays, Tuesdays, Wed, etc of each month. (I want to control for weekly seasonality but my data is monthly). Is there an easy way to to this in R? or is there a package i could use? i did

Hi , I am trying to convert the date as factor to date using "as.date" function in R. I have the date in the following format 2008-01-01 02:30 I tried to use the following command : as.Date(mydata$Date, format="%y-%m-%d ") Can somebody help me with this ? I was able to convert the format with no hour but getting difficulty with hour included. Thank you.

Hi, Is there a package for converting day-month-year type date to julian day number (JDN)? I looked around and I couldn't find any (I am pretty new to R...) Thanks and happy New Year to everybody! H. N?zhet Dalfes Professor, Istanbul Technical University Eurasia Institute of Earth Sciences +90 (532) 206-1308 [dalfes at itu.edu.tr]