Is it possible to create anonymous objects in Python?

Question

I\'m debugging some Python that takes, as input, a list of objects, each with some attributes.

I\'d like to hard-code some test values -- let\'s say, a list of four

Answer 1

I will use lambda

obj = lambda: None
obj.s = 'abb'
obj.i = 122

Answer 2

Have a look at this:

class MiniMock(object):
    def __new__(cls, **attrs):
        result = object.__new__(cls)
        result.__dict__ = attrs
        return result

def print_foo(x):
    print x.foo

print_foo(MiniMock(foo=3))

Answer 3

Another obvious hack:

class foo1: x=3; y='y'
class foo2: y=5; x=6

print(foo1.x, foo2.y)

But for your exact usecase, calling a function with anonymous objects directly, I don't know any one-liner less verbose than

myfunc(type('', (object,), {'foo': 3},), type('', (object,), {'foo': 4}))

Ugly, does the job, but not really.

Answer 4

I like Tetha's solution, but it's unnecessarily complex.

Here's something simpler:

>>> class MicroMock(object):
...     def __init__(self, **kwargs):
...         self.__dict__.update(kwargs)
...
>>> def print_foo(x):
...     print x.foo
...
>>> print_foo(MicroMock(foo=3))
3

Answer 5

Maybe you can use namedtuple to solve this as following:

from collections import namedtuple
Mock = namedtuple('Mock', ['foo'])

mock = Mock(foo=1)
mock.foo  // 1