Flatten nested dict/lists into a single list.

gistfile1.txt

def flatten_nested(content: Union[list, dict, ChainMap]) -> List[Union[str, int, float]]:
    """Flatten an arbitrary nested dictionary.

    Useful for flattening file patterns from a Yaml config.

    Example:
        >>> content = {"one": ["one_a", "one_b"], "two": "two_a"}
        >>> sorted(flatten_nested(content))
        ["one_a", "one_b", "two_a"]

    """

    def gen(iter: Union[list, dict, ChainMap, str, int, float]):
        if isinstance(iter, (dict, ChainMap)):
            yield from flatten_nested(list(iter.values()))
        elif isinstance(iter, list):
            for item in iter:
                yield from flatten_nested(item)
        else:
            yield iter

    return list(gen(content))




flatten_items = [
    (
        {
            "lvl1": {
                "lvl1a": "lvl1a",
                "lvl1b": ["lvl1bi", "lvl1bii"],
                "lvl1c": {
                    "lvl1ca": "lvl1ca",
                    "lvl1cb": "lvl1cb",
                    "lvl1cd": ["lvl1cdi", "lvl1cdii"],
                },
            },
        },
        ["lvl1a", "lvl1bi", "lvl1bii", "lvl1ca", "lvl1cb", "lvl1cdi", "lvl1cdii"],
    ),
    (
        ChainMap({"lvl1a": "lvl1a", "lvl1b": ["lvl1bi", "lvl1bii"]}, {"lvl1c": "lvl1ca"}),
        ["lvl1a", "lvl1bi", "lvl1bii", "lvl1ca"],
    ),
]


@pytest.mark.parametrize("nested_content,expected_content", flatten_items)
def test_flatten_nested(nested_content, expected_content):
    flattened_content = flatten_nested(nested_content)
    assert sorted(flattened_content) == sorted(expected_content)