[R] override date in xts time series

[arun]

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 <emorway at usgs.gov>
To: r-help at 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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