[R] series at low freq expanded into high freq

Murali.MENON at fortisinvestments.com Murali.MENON at fortisinvestments.com
Mon Apr 27 12:51:02 CEST 2009


Folks,
 
If I have a series mm of, say, monthly observations, and a series dd of
daily dates, what's a good way of expanding mm such that corresponding
to each day in dd within the corresponding month in mm, the values of mm
are repeated?
 
So e.g., if I have mm:
 
mm <- c(15, 10, 12, 13, 11)
names(mm)<-c("Nov 2008",   "Dec 2008",  "Jan 2009",   "Feb 2009",   "Mar
2009")
library(zoo)
mm <- zoo(mm, order.by = as.yearmon(names(mm), format="%b %Y"))
 
And days:
 
dd <- as.Date(c("03/11/2008", "05/11/2008",
"04/01/2009","02/02/2009","17/02/2009","13/03/2009","14/03/2009","18/03/
2009", "26/03/2009"), format="%d/%m/%Y")
 
I want to be able to create a series that looks like this:
 
03/11/2008	 15	
05/11/2008	 15	
04/01/2009	 12	
02/02/2009	 13	
17/02/2009	 13	
13/03/2009	 11	
14/03/2009	 11	
18/03/2009	 11	
26/03/2009	 11	
 
where because no daily dates in dd are in December, the final series has
no entries for December; there are two entries for November because
there are two dates in dd in November, etc.
 
Thanks,
Murali




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