Determine if a function is available in a Python module

Question

I am working on some Python socket code that\'s using the socket.fromfd() function.

However, this method is not available on all platforms, so I am writing some fallback

Answer 1

hasattr(obj, 'attributename') is probably a better one. hasattr will try to access the attribute, and if it's not there, it'll return false.

It's possible to have dynamic methods in python, i.e. methods that are created when you try to access them. They would not be in dir(...). However hasattr would check for it.

>>> class C(object):
...   def __init__(self):
...     pass
...   def mymethod1(self):
...     print "In #1"
...   def __getattr__(self, name):
...     if name == 'mymethod2':
...       def func():
...         print "In my super meta #2"
...       return func
...     else:
...       raise AttributeError
... 
>>> c = C()
>>> 'mymethod1' in dir(c)
True
>>> hasattr(c, 'mymethod1')
True
>>> c.mymethod1()
In #1
>>> 'mymethod2' in dir(c)
False
>>> hasattr(c, 'mymethod2')
True
>>> c.mymethod2()
In my super meta #2