pynsted 1.0.6

Add a method to dictionaries to get nested values

pynsted

This is a Python library which in a hackish way adds to Python dictionaries a method for getting nested values. It can be installed with pip install pynsted.

Usage

Start by importing the module: import pynsted.

Now access nested values in dictionaries by specifing path to them and using getn method:

>>> import pynsted
>>> a = {1: {2: {"foo": "bar"}}}
>>> a.getn([1, 2, "foo"])
'bar'
>>>

If at some moment there is no value, corresponding to the next key in path, None is returned:

>>> print(a.getn([1, 3, "foo"]))
None
>>>

It is possible to specify the default value, which will be returned instead of None if there is no value at the given path:

>>> a.getn([1, 3, "foo"], "new default")
'new default'
>>>

Linters

There are two problems with this module and linters:

• unused import
• nonexisting .getn() method for dictionaries

Unused import

If the import is really unused (see below why it may not be), do the following:

• for pylint put # pylint: disable=unused-import in the line right before the import and # pylint: disable=unused-import in the line right after, or pylint: disable=unused-import as an end comment into the import line
• for ruff put noqa: F401 as an end comment into the import line
• for pyright: put # pyright: reportUnusedImport=false in the line right before the import line and # pyright: reportUnusedImport=false in the line right after, or pyright: ignore as an end comment into the import line

Notice that in the case of multiple linters combination of end of line comments in the import line will not work, and you will need to do something like

# pylint: disable=unused-import
# pyright: reportUnusedImport=false
import pynsted  # noqa: F401
# pyright: reportUnusedImport=true
# pylint: enable=unused-import

Nonexisting method

Quick and dirty pylint solution

Add inte yoir pylint configuration file something like extension-pkg-whitelist=pynsted. Notice that method is insecure and allows the authors of pynsted to do whatever they want with your computer, and maybe also kill your cat.

Using protocol

The benefit of this approach that it will pacify not only pylint but pyright, ruff, and mypy, and will make import used. The idea is that pytested module defines SupportsGetn protocol, which claims the presence of getn method. You have to assert that your dictionary is BOTH dict and SupportsGetn:

assert isinstance(input_dict, dict)
assert isinstance(input_dict, pynsted.SupportsGetn)

Development

The project uses poetry tool (highly recommended!), you should know your way around. The supplied Makefile defines the following targets:

• test -- runs pytest and demands 100% test coverage
• qa -- runs test target and then runs a bunch of linters
• format -- formats the code with black and isort