FW: Finding which method is used by a function

["Cahill, Shane" <Shane.Cahill@ILIM.COM>]

Thanks to Chris Green and Chuck Taylor for responding to my question.  Their answers are posted below.

Shane

Shane,
The timeSeries class is a version 4 class, so its methods are probably not stored in an explicit function. Try using getMethods to see what version 4 classes methods are out there:

 
> getMethods("summary")
 
I think timeSeries inherits from seriesVirtual (don't quote me on that), so the method for signature "seriesVirtual" is the one you want.

 
HTH,
Chris Green
 
________________________________

Christopher G. Green (cggreen AT stat.washington.edu)
Doctoral Candidate
Department of Statistics, Box 354322, Seattle, WA, 98195-4322, U.S.A.
http://www.stat.washington.edu/cggreen/

Shane,
The “timeSeries” class is an S Version 4 class, so method dispatch is different from what you are used to. First, let’s look at what SV4 methods there are for “summary”:

> showMethods("summary")
      Database            object
 [1,] "splus"  "ANY"
 [2,] "splus"  "groupVecVirtual"
 [3,] "splus"  "numericSequence"
 [4,] "splus"  "timeZoneC"
 [5,] "splus"  "timeZoneS"
 [6,] "splus"  "timeDate"
 [7,] "splus"  "timeSpan"
 [8,] "splus"  "seriesVirtual"
 [9,] "splus"  "timeEvent"
[10,] "splus"  "timeRelative"
[11,] "splus"  "timeSequence"

The “timeSeries” class doesn’t appear there, so let’s see whether timeSeries inherits from one of the classes that does appear:

> extends("timeSeries")
[1] "timeSeries"    "series"        "seriesVirtual"

We see that “timeSeries” inherits from “seriesVirtual”, so it is the “seriesVirtual” method of summary that gets dispatched. To see what that method looks like, you can run

     showMethod("summary", "seriesVirtual")

To confirm that you have the right method, look at the output of

     selectMethod(“summary”, “timeSeries”)

Best regards,

Chuck Taylor
Insightful Corporation
Seattle, WA, USA

______________________________________________
From:   Cahill, Shane 
Sent:   14 August 2008 15:37
To:     's-news@wubios.wustl.edu'
Subject:        Finding which method is used by a function

Hi,
I would like to find out which method for the function 'summary' is used on a timeSeries object.
There does not appear to be an explicit 'summary.timeSeries' method and 'summary.default' does not return the same output as 'summary'.

I use S-PLUS 8.0 for Windows.

Kind regards,
Shane

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