[BioC] extracting one probe set

[Thomas Turner]

Dear all,

I am trying to simply extract a table with the probe intensities for a 
probe set that I specify by name.  As described in 6.2 of the manual, I 
have been trying to use this command:

ps <- probeset(affybatch, genenames = ("probe set name"))

However, I am unable to make the following command work: 

pm(ps[[1]]) 

If I ask R about my "ps", it gives me this:

$"Ag.X.66.0 CDS s at"
ProbeSet object:
  id=Ag.X.66.0 CDS s at
  pm= 1 probes x  1  chips

My affybatch includes four chips, which do not seem to be what this is 
telling me.  I am new to R, and any advice would be warmly received.

Thank you,

Tom Turner