python function - callable(object)

callable(object)

Chinese description: Check whether the object object is callable. If True is returned, object may still fail to be called; but if False is returned, calling object object will never succeed.

Note: Classes are callable, and instances of the class can only be called if they implement the __call__() method.

Version: This function is available in python2.x version. However, it was removed in python3.0 and added again in python3.2 and later versions.

English description: Return True if the object argument appears callable, False if not. If this returns true, it is still possible that a call fails, but if it is false, calling object will never succeed. Note that classes are callable (calling a class returns a new instance); class instances are callable if they have a __call__() method.

Code example:

>>> callable(0)
False
>>> callable("mystring")
False
>>> def add(a, b):
…     return a + b
…
>>> callable(add)
True
>>> class A:
…      def method(self):
…         return 0
…
>>> callable(A)
True
>>> a = A()
>>> callable(a)
False
>>> class B:
…     def __call__(self):
…         return 0
…
>>> callable(B)
True
>>> b = B()
>>> callable(b)
True