On Nov 12, 1:35 pm, Terry Reedy <[EMAIL PROTECTED]> wrote: > Cristina Yenyxe González García wrote: > > > 2008/11/12 Joe Strout <[EMAIL PROTECTED]>: > >> So I need functions to assert that a given identifier quacks like a string, > >> or a number, or a sequence, or a mutable sequence, or a certain class, or > >> so > >> on. (On the class check: I know about isinstance, but that's contrary to > >> duck-typing -- what I would want that check to do instead is verify that > >> whatever object I have, it has the same public (non-underscore) methods as > >> the class I'm claiming.) > > >> Are there any standard methods or idioms for doing that? > > > You can use hasattr(object, name), with 'name' as the name of the > > public method to check. It returns True if the object responds to that > > method, False otherwise. > > Too hard. For methods, which are what define duck species, and any > attribute guaranteed to not be null, "assert ob.name" is equivalent to > "assert hasattr(ob, 'name')".
As you just showed they're not; one raises AttributeError and the other AssertionError. Not that it matters much but these are typically reported differently by testing frameworks. George -- http://mail.python.org/mailman/listinfo/python-list
