monty.collections module
Useful collection classes, e.g., tree, frozendict, etc.
class monty.collections.AttrDict(*args, **kwargs)
Bases: dict
Allows to access dict keys as obj.foo in addition to the traditional way obj[‘foo’]”
Example
>>> d = AttrDict(foo=1, bar=2)
>>> assert d["foo"] == d.foo
>>> d.bar = "hello"
>>> assert d.bar == "hello"
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
copy()
- Returns Copy of AttrDict
class monty.collections.FrozenAttrDict(*args, **kwargs)
Bases: frozendict
A dictionary that:
* does not permit changes.
* Allows to access dict keys as obj.foo in addition
to the traditional way obj[‘foo’]
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
class monty.collections.MongoDict(*args, **kwargs)
Bases: object
This dict-like object allows one to access the entries in a nested dict as attributes. Entries (attributes) cannot be modified. It also provides Ipython tab completion hence this object is particularly useful if you need to analyze a nested dict interactively (e.g. documents extracted from a MongoDB database).
>>> m = MongoDict({'a': {'b': 1}, 'x': 2})
>>> assert m.a.b == 1 and m.x == 2
>>> assert "a" in m and "b" in m.a
>>> m["a"]
{'b': 1}
NOTE: Cannot inherit from ABC collections.Mapping because otherwise dict.keys and dict.items will pollute the namespace. e.g MongoDict({“keys”: 1}).keys would be the ABC dict method.
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
class monty.collections.Namespace(*args, **kwargs)
Bases: dict
A dictionary that does not permit to redefine its keys.
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
update(*args, **kwargs)
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
monty.collections.dict2namedtuple(*args, **kwargs)
Helper function to create a namedtuple
from a dictionary.
Example
>>> t = dict2namedtuple(foo=1, bar="hello")
>>> assert t.foo == 1 and t.bar == "hello"
>>> t = dict2namedtuple([("foo", 1), ("bar", "hello")])
>>> assert t[0] == t.foo and t[1] == t.bar
WARNING:
- The order of the items in the namedtuple is not deterministic if kwargs are used. namedtuples, however, should always be accessed by attribute hence this behaviour should not represent a serious problem.
- Don’t use this function in code in which memory and performance are crucial since a dict is needed to instantiate the tuple!
class monty.collections.frozendict(*args, **kwargs)
Bases: dict
A dictionary that does not permit changes. The naming violates PEP8 to be consistent with standard Python’s “frozenset” naming.
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
update(*args, **kwargs)
- Parameters
- args – Passthrough arguments for standard dict.
- kwargs – Passthrough keyword arguments for standard dict.
monty.collections.tree()
A tree object, which is effectively a recursive defaultdict that adds tree as members.
Usage:
x = tree()
x[‘a’][‘b’][‘c’] = 1
- Returns A tree.