has_method

[Peter Hansen]

Gandalf wrote:
> 
> Does anyone knows how to tell if an object has a method with a given 
> name? How can I access that method?
> 
> For attributes, it is easy:
> 
> class A(object):
>    a = 12
>    b = 'Python'
> 
> a = A()
> a.__dict__.has_key('a')   # True
> a.__dict__.has_key('b')   # True
> a.__dict__.has_key('c')   # False
> 
> But it won't work for methods. Thanks in advance.

Don't access __dict__ directly.  In fact, most of the time
the presence of the __ underscores is to warn you that you
are doing something unusual... here's the better way:

if callable(getattr(a, 'b')):
     print 'has a method called b'
else:
     print 'no method called b'

getattr(obj, name) retrieves the attribute, and callable()
checks if it's a method (roughly speaking... not quite but
good enough for your purposes I believe).  Look in the docs
for the __builtin__ module to learn about these and other
such useful functions. 
http://docs.python.org/lib/built-in-funcs.html#built-in-funcs

-Peter