[R-SIG-Finance] Dates manipulation

[Manoj]

Hi All,
   I am using version 2,8,1 and working with zoo library.

   The sample/dummy data-set i am working off takes the following structure:

Date	Ticker	Price
2009-04-21     	X 	2.32
2009-04-22     	X 	2.35
2009-04-23     	X 	2.34
2009-04-21     	Y	10.2
2009-04-22     	Y	10.32
2009-04-23     	Y	10.15

   The data-frame consist of Date as a Date object, Ticker and Price.
Price can be uniquely identified by Date & Ticker.

   One of the issues with creating a zoo object with above data-set is
the fact that the unique key is basically a composite key so it's not
purely time-series data but does take the format of panel data.

 I want to be able to perform normal data function (lag,time etc) on
the above data-set for example, lag would return all the rows except
for ticker X&Y for 2009-04-23.

  Is there anyway, i can sub-class zoo object to achieve this functionality?

  Any suggestions would be greatly appreciated - thanks in advance.


Manoj