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python-attrs

Using attr.asdict() filter with a callable

I'm trying to create a method on my class which will return only public properties as a dict. I am struggling with the syntax. This is what I tried unsuccessfully:

@attr.s
class C:
    x = attr.ib()
    _y = attr.ib()

    def _no_privates(a, _):
       return not a.name.startswith("_")

    def public_properties_to_dict(self):
       return attr.asdict(self, filter=attr.filters.include(_no_privates))
Solution

  • In you example, _no_privates is not function but a method.

    The solution which I consider better would be to move _no_privates out of the class into the top scope. It's a function that takes an argument and returns a value based on that argument and nothing else.

    If you insist on making _no_privates a method, you can write filter=attr.filters.include(self._no_privates).

    However the signature of _not_privates is wrong in any case. If it's a function, it should only take a. If it's a method, the first argument is self, followed by a.