Hello Arun,
My earlier example was not very robust. It seems issues arise during DST:
library(xts)
library(lubridate)
x.Date <- rep("1/1/2004",times=5)
x.Times<- c("01:15:00", "01:30:00", "01:45:00",
"02:00:00", "02:30:00", "03:00:00", "03:15:00")
x<-paste(x.Date,x.Times)
y.Date <- rep("4/4/2004",times=4)
y.Times<- c("01:15:00", "01:30:00", "01:45:00",
"02:00:00", "02:30:00", "03:30:00")
y<-paste(y.Date,y.Times)
fmt <- "%m/%d/%Y %H:%M:%S"
x.1<-xts(1:7, as.POSIXct(x, format=fmt))
y.1<-xts(1:6, as.POSIXct(y, format=fmt))
index(y.1)<-update(index(y.1),month=unique(month(index(x.1))))
y.1
# [,1]
#2004-01-04 01:15:00 1
#2004-01-04 01:30:00 2
#2004-01-04 01:45:00 3
#<NA> 4
#<NA> 5
#2004-01-04 03:30:00 6
So, I'm wondering if there are built in functions/commands for dealing
with this? The code here is a smaller example of a larger problem I'm
working on. In the larger problem, the 'update' command you provided me
with isn't updating, nor is it throwing an error. I'm wondering if its
related to DST? Here is some example R output from the larger problem
highlighting the behavior:
xs[[i]][2:3]
# xQ xSC
#2004-01-01 00:15:00 0.43 NA
#2004-01-01 00:30:00 0.43 2240
xs[[j]][2:3]
# xQ xSC
#2004-04-04 00:15:00 669 NA
#2004-04-04 00:30:00 664 2320
The next line of code shows that the update command is return the desired
result:
update(index(xs[[j]][2:3]),month=unique(month(index(xs[[i]][2:3]))))
# "2004-01-04 00:15:00 PST" "2004-01-04 00:30:00 PST"
The next line shows what the current index is:
index(xs[[j]][2:3])
# "2004-04-04 00:15:00 PST" "2004-04-04 00:30:00 PST"
Now I try running the code you showed me
index(xs[[j]][2:3])<-update(index(xs[[j]][2:3]),month=unique(month(index(xs[[i]][2:3]))))
#Warning message:
#In NextMethod(.Generic) :
# number of items to replace is not a multiple of replacement length
While there was a warning, there was no error, so I'm surprised that the
index wasn't updated?
xs[[j]][2:3]
# xQ xSC
#2004-04-04 00:15:00 669 NA
#2004-04-04 00:30:00 664 2320
If its not day light savings, do you have any other thoughts as to what
the problem might be?
From:
arun <smartpink...@yahoo.com>
To:
Eric Morway <emor...@usgs.gov>
Cc:
R help <r-help@r-project.org>
Date:
11/02/2012 06:22 AM
Subject:
Re: [R] override date in xts time series
HI,
You can use:
library(lubridate)
index(y.1)<-update(index(y.1),month=1)
#or
index(y.1)<-update(index(y.1),month=unique(month(index(x.1))))
y.1
[,1]
#2004-01-01 00:00:00 1
#2004-01-01 00:15:00 2
#2004-01-01 00:45:00 3
#2004-01-01 01:00:00 4
A.K.
----- Original Message -----
From: Eric Morway <emor...@usgs.gov>
To: r-help@r-project.org
Cc:
Sent: Friday, November 2, 2012 7:55 AM
Subject: [R] override date in xts time series
Using the following bit of R, I'm wondering if there is a way to
override/manipulate/replace the date in one xts time series with the
date of
another xts time series while not affecting/changing the times of the
xts
time series?
library(xts)
x.Date <- rep("1/1/2004",times=5)
x.Times<- c("00:00:00", "00:15:00", "00:30:00",
"00:45:00", "01:00:00")
x<-paste(x.Date,x.Times)
y.Date <- rep("3/1/2004",times=4)
y.Times<- c("00:00:00", "00:15:00",
"00:45:00", "01:00:00")
y<-paste(y.Date,y.Times)
fmt <- "%m/%d/%Y %H:%M:%S"
x.1<-xts(1:5, as.POSIXct(x, format=fmt))
y.1<-xts(1:4, as.POSIXct(y, format=fmt))
If possible, I'd like query the date of x.1 and use it to override the
date
in y.1, leaving the times as they are. So the current output looks
like
this:
x.1
# [,1]
#2004-01-01 00:00:00 1
#2004-01-01 00:15:00 2
#2004-01-01 00:30:00 3
#2004-01-01 00:45:00 4
#2004-01-01 01:00:00 5
y.1
# [,1]
#2004-03-01 00:00:00 1
#2004-03-01 00:15:00 2
#2004-03-01 00:45:00 3
#2004-03-01 01:00:00 4
But I would like change y.1 to look like the following by using the
date of
x.1 (notice the month was updated to match x.1):
y.1
[,1]
2004-01-01 00:00:00 1
2004-01-01 00:15:00 2
2004-01-01 00:45:00 3
2004-01-01 01:00:00 4
Thanks, Eric
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and provide commented, minimal, self-contained, reproducible code.
