python-3.7

Python’s pathlib get parent’s relative path

by

Use the PurePath.relative_to() method to produce a relative path. You weren’t very clear as to how the base path is determined; here are two options: secondparent = path.parent.parent homedir = pathlib.Path(r’C:\users\user1′) then just use str() on the path.relative_to(secondparent) or path.relative_to(homedir) result. Demo: >>> import pathlib >>> path = pathlib.Path(r’C:\users\user1\documents\importantdocuments’) >>> secondparent = path.parent.parent >>> homedir … Read more

type hint for an instance of a non specific dataclass

by

Despite its name, dataclasses.dataclass doesn’t expose a class interface. It just allows you to declare a custom class in a convenient way that makes it obvious that it is going to be used as a data container. So, in theory, there is little opportunity to write something that only works on dataclasses, because dataclasses really … Read more

How to make “keyword-only” fields with dataclasses?

by

Update: coming in Python 3.10, there’s a new dataclasses.KW_ONLY sentinel that works like this: @dataclasses.dataclass class Example: a: int b: int _: dataclasses.KW_ONLY c: int d: int Any fields after the KW_ONLY pseudo-field are keyword-only. There’s also a kw_only parameter to the dataclasses.dataclass decorator, which makes all fields keyword-only: @dataclasses.dataclass(kw_only=True) class Example: a: int b: … Read more

“ indirect fixture” error using pytest. What is wrong?

by

TL;DR – The problem is with the line @pytest.mark.parametrize(“entrada”,”esperado”,[ … ]) It should be written as a comma-separated string: @pytest.mark.parametrize(“entrada, esperado”,[ … ]) You got the indirect fixture because pytest couldn’t unpack the given argvalues since it got a wrong argnames parameter. You need to make sure all parameters are written as one string. Please … Read more

How do I document a constructor for a class using Python dataclasses?

by

The napoleon-style docstrings as they are described in the sphinx docs (see the ExampleError class for their take on it) explicitly touch on your case: The __init__ method may be documented in either the class level docstring, or as a docstring on the __init__ method itself. And if you do not want this behavior, you … Read more

Python 3.7 on Ubuntu 20.04

by

Do you need Ubuntu 20.04? Ubuntu 18.04 comes with Python 3.6, and 3.7 available. If you do, the deadsnakes PPA has Python 3.5-3.7 for Ubuntu 20.04 (Focal). To add it and install: sudo add-apt-repository ppa:deadsnakes/ppa sudo apt-get install python3.7 P.s. I’m not a dev and have no experience with Tensorflow so take this with a … Read more

AttributeError: type object ‘Callable’ has no attribute ‘_abc_registry’

by

Try uninstalling typing: pip uninstall typing or downgrading python to 3.6. There seems to be a problem with typing in 3.7 If after that you get: AttributeError: module ‘typing’ has no attribute ‘_ClassVar’ try pip uninstall dataclasses. For more info refer to: https://github.com/RTIInternational/gobbli/issues/10

How can I get Python 3.7 new dataclass field types?

by

Inspecting __annotations__ gives you the raw annotations, but those don’t necessarily correspond to a dataclass’s field types. Things like ClassVar and InitVar show up in __annotations__, even though they’re not fields, and inherited fields don’t show up. Instead, call dataclasses.fields on the dataclass, and inspect the field objects: field_types = {field.name: field.type for field in … Read more