Python hasattr() - How to check if the object or instance has an attribute or property

The hasattr() checks if the object or instance has an attribute. It is a built-in function in Python.

class User:

    def __init__(self, name):
        self.name = name

    def buy(self):
        print(self.name + ' is buying')

    def sell(self):
        print(self.name + ' is selling')


u = User(name='Josh')

if hasattr(u, 'name'):
    print('name')

if hasattr(u, 'buy'):
    print('buy')

if hasattr(u, 'do'):
    print('do')

# name
# buy

do is not printed because the user object doesn't have the do attribute. You can get the attributes of an instance by __dir__().

class User:

    def __init__(self, name):
        self.name = name

    def buy(self):
        print(self.name + ' is buying')

    def sell(self):
        print(self.name + ' is selling')


u = User(name='Josh')

d = u.__dir__()

print(d)
# ['name', '__module__', '__init__', 'buy', 'sell', '__dict__', '__weakref__', '__doc__', '__repr__', '__hash__', '__str__', '__getattribute__', '__setattr__', '__delattr__', '__lt__', '__le__', '__eq__', '__ne__', '__gt__', '__ge__', '__new__', '__reduce_ex__', '__reduce__', '__subclasshook__', '__init_subclass__', '__format__', '__sizeof__', '__dir__', '__class__']