How to test if a class attribute is an instance method.

Question

In Python I need to efficiently and generically test whether an attribute of a class is an instance method. The inputs to the call would be the name of the attribute being checked (a string) and an object.

hasattr returns true regardless of whether the attribute is an instance method or not.

Any suggestions?

---

For example:

class Test(object):
    testdata = 123

    def testmethod(self):
        pass

test = Test()
print ismethod(test, 'testdata') # Should return false
print ismethod(test, 'testmethod') # Should return true

Answer 1

import types

print isinstance(getattr(your_object, "your_attribute"), types.MethodType)

Answer 2

def hasmethod(obj, name):
    return hasattr(obj, name) and type(getattr(obj, name)) == types.MethodType

Answer 3

You can use the inspect module:

class A(object):
    def method_name(self):
        pass


import inspect

print inspect.ismethod(getattr(A, 'method_name')) # prints True
a = A()
print inspect.ismethod(getattr(a, 'method_name')) # prints True

Answer 4

This function checks if the attribute exists and then checks if the attribute is a method using the inspect module.

import inspect

def ismethod(obj, name):
    if hasattr(obj, name):
        if inspect.ismethod(getattr(obj, name)):
            return True
    return False

class Foo:
    x = 0
    def bar(self):
        pass

foo = Foo()
print ismethod(foo, "spam")
print ismethod(foo, "x")
print ismethod(foo, "bar")