Extracting Coefficients and Such from mle2 Output

Marc Schwartz <marc_schwartz <at> comcast.net> writes:

on 02/01/2009 10:45 AM David Winsemius wrote:

Let me  admit at this point that I am not really sure that S4 classes is
the correct classification of such "@"-using extraction processes. The
documentation refers to "formal methods" and I don't yet have enough
knowledge to know that how tightly slots and formal classes are linked
with S4 or S3.

David,

The use of '@' as a slot extractor is specific to S4 methods and you
will actually get an error if attempting to use it on other object
types. As per the Details section of ?"@":

My other two cents about this issue:

 David is quite right that you can basically think of "@"
as equivalent to "$" for getting bits out of S4 objects.
However ... in general S4 classes make it harder to get
internal bits out of objects, and in some sense they're
really *supposed* to make it harder.  Really the thing to
do when you encounter information that's buried somewhere
in an S4 object, the appropriate solution is what you did --
write to the author and say "why isn't there an accessor
method [the technical jargon for functions like coef()]
to get this piece of information out of this object, or
why isn't it properly documented? (Or is there some 
reason that I shouldn't be trying to access this piece
of information?)"

  cheers
   Ben Bolker