Mark Carter wrote: > Suppose I want to define a function "safe", which returns the argument > passed if there is no error, and 42 if there is one. So the setup is > something like: > > def safe(x): > # WHAT WOULD DEFINE HERE? > > print safe(666) # prints 666 > print safe(1/0) # prints 42 > > I don't see how such a function could be defined. Is it possible?
1/0 is evaluated before safe() is called. Therefore safe() has no chance to catch the exception. You have to move the evaluation into the safe() function: >>> def safe(deferred, default=42, exception=Exception): ... try: ... return deferred() ... except exception: ... return default ... >>> print safe(lambda: 666) 666 >>> print safe(lambda: 1/0) 42 -- http://mail.python.org/mailman/listinfo/python-list
