R help - May 2010 - Isn't aggreate.zoo supposed to work with POSIXct (zoo/TTR/xts issue)?

library(xts)
library(TTR)

ndx = getYahooData("^NDX")
aa = ndx$Close
bb = aggregate(aa, as.yearweek, tail, 1)

The last operation takes forever, and then the bb dates are messed up. The
following produces the desired result:

time(aa) = as.Date(time(aa))
bb = aggregate(aa, as.yearweek, tail, 1)

The index of ndx and aa is of POSIXct (as reported by is(time(ndx))) , which
apparently causes problems. Isn't zoo (and xts) supposed to work properly
regardless of the type of index? Is this a bug in one of the libraries?

Thanks in advance,
Ivan
 		 	   		  
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On Mon, 17 May 2010, ivan popivanov wrote:
>
> library(xts)
> library(TTR)
>
> ndx = getYahooData("^NDX")
> aa = ndx$Close
> bb = aggregate(aa, as.yearweek, tail, 1)
>
> The last operation takes forever, and then the bb dates are messed up.
The problem is problem due to the as.yearweek() function which is neither 
part of "zoo" nor "xts" (nor any other package I can think
of).
Z
> The following produces the desired result:
>
> time(aa) = as.Date(time(aa))
> bb = aggregate(aa, as.yearweek, tail, 1)
>
> The index of ndx and aa is of POSIXct (as reported by is(time(ndx))) ,
which apparently causes problems. Isn't zoo (and xts) supposed to work
properly regardless of the type of index? Is this a bug in one of the libraries?
>
> Thanks in advance,
> Ivan
>
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> 30 days of prizes: Hotmail makes your day easier! Enter Now.
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