Python check instances of classes

isinstance() is your friend here. It returns a boolean and can be used in the following ways to check types.

if isinstance(obj, (int, long, float, complex)):    print obj, "is a built-in number type"if isinstance(obj, MyClass):    print obj, "is of type MyClass"

Hope this helps.

Have you tried isinstance() built in function?

You could also look at hasattr(obj, '__class__') to see if the object was instantiated from some class type.

If you want to check that an object of user defined class and not instance of concrete built-in types you can check if it has __dict__ attribute.

>>> class A:...     pass... >>> obj = A()>>> hasattr(obj, '__dict__')True>>> hasattr((1,2), '__dict__')False>>> hasattr(['a', 'b', 1], '__dict__')False>>> hasattr({'a':1, 'b':2}, '__dict__')False>>> hasattr({'a', 'b'}, '__dict__')False>>> hasattr(2, '__dict__')False>>> hasattr('hello', '__dict__')False>>> hasattr(2.5, '__dict__')False>>> 

If you are interested in checking if an instance is an object of any class whether user defined or concrete you can simply check if it is an instance of object which is ultimate base class in python.

class A:    passa = A()isinstance(a, object)Trueisinstance(4, object)Trueisinstance("hello", object)Trueisinstance((1,), object)True