Dear All,
I want to test whether a method exists for given object. For example,
whether a function "deviance" is defined for an object of the "lm" class.
My imperfect understanding leads me to think something like
hasMethod("deviance", object)
hasMethod("deviance", "lm")
existsMethod("deviance", signature(class="lm"))
or similar might work (I don't fully understand how to manipulate
signatures), but all the variations on this I have tried return FALSE.
(Except, interestingly, when I first load library lme4, after which all
return TRUE even for non-existant classes and functions).
I realize there are several ways in which R implements function
polymorphism and that this is all documented somewhere but a hint would
save me considerable time. I would also prefer not to resort to the hack
solution of try()ing the function with the object and then catching the
error to determine whether it was defined.
Thanks,
Will
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Dr William Valdar ++44 (0)1865 287 589
Wellcome Trust Centre [EMAIL PROTECTED]
for Human Genetics, Oxford www.well.ox.ac.uk/~valdar
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