Aggregating tick by tick timeSeries [NC]

Thank you Jeff,


my aim was to calculate standard statistics + volume weighted prices and
spreads.


I will try out the xts package, but I am wondering if it can aggregate
Multivariate timeSeries (e.g, (spread, volume) or (price,volume)).


thanks again


|------------------------------                                            
|            jeff.a.ryan at gmail                                             
|            .com                                                          
|                                                                          
|            03/05/2008 16:21                                              
|                                                                          
                                                                           
                                                                           
                                                                        To 
                                               Anass                       
                                               MOUHSINE/fr/socgen at socgen   
                                                                        cc 
                                               r-sig-finance at stat.math.eth 
                                               z.ch                        
                                                                   Subject 
                                               Re: [R-SIG-Finance]         
                                               [R-sig-finance] Aggregating 
                                               tick by tick timeSeries     
                                               [C1]                        
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Anass,

If you want the mean/sd/etc for each hour ?aggregate from zoo will do
the job very well. To get there from timeSeries you can use the new
'xts' package:

myTS [a timeSeries object]

as.xts(myTS) [ now an 'xts' object - which inherits from zoo]

--or--

as.zoo(myTS)

you can even put it back to a timeSeries with little information loss
if you use xts via 'reclass' (changing the series outside of xts
functions currently isn't perfect - but it is good)

If you want to just aggregate the data into OHLC per time period -
to.period in xts is fast and flexible:

to.period(myTS,'minutes',15)
to.period(myTS,'hours')
to.monthly(myTS)

All these work by converting and reconverting to an 'xts' class
internally - so most any (including timeSeries) class will just work
with the function.  In addition it is all compiled code - so it works
well.

One caveat - you'll need to get the most recent xts from
http://r-forge.r-project.org/projects/xts - as there was a minor bug
in the transition of 'to.period' code from quantmod to xts.

Jeff

On Wed, Mar 5, 2008 at 8:21 AM,  <anass.mouhsine at sgcib.com> wrote:

 Hi guys,


 I have a timeSeries object like this one
                        V10
 2005-04-08 17:31:41 0.01
 2005-04-08 17:31:57 0.02
 2005-04-08 17:32:00 0.02
 2005-04-08 17:32:57 0.02
 2005-04-08 17:38:34 0.02
 2005-04-08 17:38:49 0.01

 and I would like to aggregate the timeSeries in hours or minutes in

order

 to apply whatever function on the aggregated data (e.g mean, standard

dev,

 etc...)
 I have seen some aggreagation functions like aggregate in the fSeries
 package but it aggregates only monthly or quaterly.
 I am sure some of you guys were faced to this kind of issue.

 Could anyone give me some hints on how to solve my problem?

 thanks in advance

 Anass