similar to: date

R is not for Relational, but could be... I was musing on data.frames when I decided what I needed was a SQL like 'select' statement. Before I get involved in writing something like that, has anyone else written anything that allows a relational like algebra on data.frames? Thanks, John Carter EMail: ece at dwaf-hri.pwv.gov.za Telephone : 27-12-808-0374x194 Fax:-

Hello, I've encountered the need to cut some chron objects of the form: R> mychron <- chron(sort(runif(10, 0, 10))) R> mychron [1] (01/01/70 16:36:20) (01/02/70 00:08:46) (01/03/70 16:54:49) [4] (01/04/70 06:45:00) (01/07/70 06:21:24) (01/07/70 18:28:44) [7] (01/08/70 00:47:05) (01/08/70 05:11:44) (01/10/70 01:07:53) [10] (01/10/70 17:46:53) into arbitrary (e.g. a given number

Dear all, I'm not sure whether this is a bug or not... But some help would be greatly appreciated. I have a dataframe, which I read in using read.xport (from the foriegn library) as the orginal data is in SAS format. 3 columns of this dataset are supposed to be dates, but read.xport doesn't recognise them as dates (all columns are read in as mode numeric). So I load up the date library

Another beginner's question. Still trying trying to read and and plot a simple tds-value vs time. input file: onedat date time tds 1997-12-29 13:35:00 411 > onedat<-read.table("onedat",header=T) attach(onedat) > x<-chron(dates=as.vector(date),times=as.vector(time), format=c("y-md","h:m:s")) > x [1] (97-12-29 13:35:00) See my problem? Chron

The problem with POSIXt is that you must consider timezones and daylight vs. standard time issues even if you don't want to. This violates modularity (viz. your routines becomes coupled to unrelated information) and leads to subtle errors where different routines are assuming different time zones. The problem is that the time, date, day of the week, month, etc. of a date depend on its

------------------------------------------------- SAMPLE SCRIPT: x<-rnorm(50) y<-12*x+30*rnorm(10) ff<-lm(y~x) sink("output.txt") print(ff) # this work give basic coefficients summary(ff) # should give Rsquare etc sink() ------------------------------------------------- Having fitted a curve on a data set, I am trying to write all the statistics about the fit to a file. In

Hi, I've been using the chron package to convert excel time into month/day/year and h:m:s formats, specifically for use as axis labels. I've come across something I don't quite understand. ### Here are some excel times: dat = c(39083, 39083.00694, 39083.01389, 39083.02083, 39083.02778, 39083.03472, 39083.04167, 39083.04861, 39083.05556, 39083.0625 ) ### I create

Hi. I frequently convert date and time data to and from character representations. I'm frustrated with chron, because 'seconds' are required to create a time object (my input data never has seconds). More importantly, I cannot make chron print the format 12/30/2006 (which my output data requires). I really like the format flexibility of strftime() and strptime(), but of course

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

Proper calendar dates in R are great for plotting and calculating. However for the non-wonks among us, they can be very frustrating. I have recently discussed the pains that people in my lab have had with dates in R. Especially the frustration of bringing date data into R from Excel, which we have to do a lot. Please find below a simple analgesic for R date importation that I discovered over

the date were created with chron with this argument format=c(dates="Y/m/d", times="H:M:S")) so I have the dates being displayed as (10/06/22 12:00:00) I would like to have them displayed as "2010-06-22 12:00:00" or "%Y-%m-%d %H:%M:%S" and then I can convert these for mergeing with another data frame x <- (structure(c(14464, 14464.0104166667,

Dear R People Here is an interesting problem: > library(pastecs) > a <- 1:100 > b <- daystoyears(a,datemin="1/1/2003",dateformat="m/d/Y") > b [1] 2002.999 2003.002 2003.005 2003.008 2003.010 2003.013 2003.016 2003.018 2003.021 2003.024 2003.027 2003.029 2003.032 [14] 2003.035 2003.038 2003.040 2003.043 2003.046 2003.049 2003.051 2003.054 2003.057 2003.060

How do I parse a date "yyyymmdd"? I tried asking chron(s, "ymd") but that didn't work. Would the date parsing routines of the Date class of 1.9 grok this? -- Ajay Shah Consultant ajayshah at mayin.org Department of Economic Affairs http://www.mayin.org/ajayshah Ministry of Finance, New Delhi

Hello, today I've updated on the newest R-Version. But sadly a function I needed didnt want to work: The input is e.g. days(as.Date("21-07-2005","%d-%m-%y")) the error is: Fehler in Math.Date(dts): floor nicht definiert f??r Date Objekte (Error in Math.Date(dts): floor not defined for date objects) Same for year. Only months gives me the correct output. In Version

I was just looking for an easy way to convert between COM datetime and chron datetime (both ways.) I found examples on the list, but they involved origin. Does anyone have functions for converting COM datetime <-> chron datetimethat work "safely"? David L. Reiner > -----Original Message----- > From: Gabor Grothendieck [mailto:ggrothendieck@gmail.com] >

Hello, I am attempting to use R as part of a time-series analysis investigating the influence of meteorological factors on health outcomes. The test csv dta file that i am working with contains a complete daily set of the variables ?DATE?, ?ADMINS?, ?NOX?, ?TEMP? across a 5 year period (1827 days). Within attempting to fit a GLM, I believe that I am having difficulty with the ns function,

I would like a sequence of dates with a time step of 15 minutes starting: 1/1/2006 00:00:00 - 12/31/2006 23:45:00 function(x) { chron(sub(" .*", "", x), gsub(".* (.*)", "\\1:00", x)) } this is the piece of code I use to read in zoo objects for any help I would be grateful I have tried sequence and I can not seem to get it to work -- Let's not

Hi,all I only got the time data such as: tms<-c("19:30:23","18:39:10".....) I want to manipulate this time series data. For example, plus one second(or minute) or minus one second This data only has the time(h:m:s), without the date. I know that there are chron package, ISOPix class and the timeDate class, but all these class need the input of date. How can we

Full_Name: Kem Phillips Version: 2.7.1 (2008-06-23) OS: Windows Xp professional Submission from: (NULL) (98.221.200.108) The Hmisc function describe fails, giving the error message: Error in formatDateTime(dd, atx, !timeUsed) : could not find function "format.dates" Loading the chron package, where function dates apparently resides, does not fix the problem. Note

Full_Name: Xiao Gang FAN Version: 2.4.0 OS: Windows Submission from: (NULL) (159.50.101.9) > library(chron) > as.Date(as.POSIXct(strptime("1994-01-24","%Y-%m-%d"))) [1] "1994-01-23"