Module `attrbox.fn`

Generally useful functions.

Global variables

var AnyList: Generic list.
var AnyDict: Generic dict.
var OnlyReadDict: dict that will only be read.
var AnyListDict: Generic list or dict.
var AnyIndex: Index into a list or dict.

Functions

def get_path(src: SupportsItem, path: Union[str, int, Sequence[Union[str, int]]], default: Optional[Any] = None) ‑> Any

Get the value indicated by path or return default if it is not found.

Args

src : SupportsItem: typically a list or a dict
path : AnyIndex: path to the value
default : Any, optional: value to return if path is not found. Defaults to None.

Returns

Any: path value or default if it is not found.

Examples

>>> get_path({'a': 1}, 'a')
1
>>> get_path({'a': [1, {'b': 2}]}, ['a', 1, 'b'])
2

def set_path(dest: Union[List[Any], Dict[Any, Any]], path: Union[str, int, Sequence[Union[str, int]]], value: Any, cls_dict: Type[Dict[Any, Any]] = builtins.dict, cls_list: Type[List[Any]] = builtins.list) ‑> Union[List[Any], Dict[Any, Any]]

Set a deeply nested value.

Args

dest : Box: a list or dict
path : BoxIndex: index or Sequence into dest
value : Any: the value to set
cls_dict : Type[dict], optional: Constructor for Mapping objects. Defaults to dict.
cls_list : Type[list], optional: Constructor for List objects. Defaults to list.

Returns

Box: dest modified according to the path. New dict and list objects will be created if they do not exist.

Examples

>>> item = {'a': [{'b': {'c': 3}}]}
>>> set_path(item, ['a', 0, 'b', 'c'], 4)
{'a': [{'b': {'c': 4}}]}
>>> set_path(item, ['a', 1, 'd'], 5)
{'a': [{'b': {'c': 4}}, {'d': 5}]}

def dict_merge(dest: Dict[Any, Any], *sources: Mapping[Any, Any], cls_dict: Type[Dict[Any, Any]] = builtins.dict) ‑> Dict[Any, Any]

Generic recursive merge for dict-like objects.

NOTE: Every nested dict will pass through cls_dict.

Args

dest : AnyDict: dict into which sources are merged
*sources : OnlyReadDict: dicts to merge
cls_dict : Type[AnyDict], optional: constructor for default dict. Defaults to dict.

Returns

AnyDict: dest now with merged values

Examples

>>> a = {"b": {"c": 1}, "d": 2}
>>> b = {"b": {"c": 2, "e": 3}, "d": 2}
>>> c = {"d": {"e": 5}}
>>> dict_merge(a, b, c)
{'b': {'c': 2, 'e': 3}, 'd': {'e': 5}}

Classes

class SupportsItem (*args, **kwargs)

Protocol for k in x, x[k], and x[k] = v.

Expand source code

@runtime_checkable
class SupportsItem(Protocol):  # pragma: no cover
    """Protocol for `k in x`, `x[k]`, and `x[k] = v`."""

    def __contains__(self, key: Any) -> bool:
        """Return `True` if `key` exists, `False` otherwise."""
        return False

    def __getitem__(self, key: Any) -> Any:
        """Return value of `key`."""

    def __setitem__(self, key: Any, value: Any) -> Optional[Any]:
        """Set `key` to `value`."""

Ancestors

typing.Protocol
typing.Generic