infinidat/munch

A Munch is a Python dictionary that provides attribute-style access (a la JavaScript objects).

munch

Installation

pip install munch

Usage

munch is a fork of David Schoonover's Bunch package, providing similar functionality. 99% of the work was done by him, and the fork was made mainly for lack of responsiveness for fixes and maintenance on the original code.

Munch is a dictionary that supports attribute-style access, a la JavaScript:

>>> from munch import Munch
>>> b = Munch()
>>> b.hello = 'world'
>>> b.hello
'world'
>>> b['hello'] += "!"
>>> b.hello
'world!'
>>> b.foo = Munch(lol=True)
>>> b.foo.lol
True
>>> b.foo is b['foo']
True

Dictionary Methods

A Munch is a subclass of dict; it supports all the methods a dict does:

>>> list(b.keys())
['hello', 'foo']

Including update():

>>> b.update({ 'ponies': 'are pretty!' }, hello=42)
>>> print(repr(b))
Munch({'hello': 42, 'foo': Munch({'lol': True}), 'ponies': 'are pretty!'})

As well as iteration:

>>> [ (k,b[k]) for k in b ]
[('hello', 42), ('foo', Munch({'lol': True})), ('ponies', 'are pretty!')]

And "splats":

>>> "The {knights} who say {ni}!".format(**Munch(knights='lolcats', ni='can haz'))
'The lolcats who say can haz!'

Serialization

Munches happily and transparently serialize to JSON and YAML.

>>> b = Munch(foo=Munch(lol=True), hello=42, ponies='are pretty!')
>>> import json
>>> json.dumps(b)
'{"foo": {"lol": true}, "hello": 42, "ponies": "are pretty!"}'

If JSON support is present (json or simplejson), Munch will have a toJSON() method which returns the object as a JSON string.

If you have PyYAML installed, Munch attempts to register itself with the various YAML Representers so that Munches can be transparently dumped and loaded.

>>> b = Munch(foo=Munch(lol=True), hello=42, ponies='are pretty!')
>>> import yaml
>>> yaml.dump(b)
'!munch.Munch\nfoo: !munch.Munch\n  lol: true\nhello: 42\nponies: are pretty!\n'
>>> yaml.safe_dump(b)
'foo:\n  lol: true\nhello: 42\nponies: are pretty!\n'

In addition, Munch instances will have a toYAML() method that returns the YAML string using yaml.safe_dump(). This method also replaces __str__ if present, as I find it far more readable. You can revert back to Python's default use of __repr__ with a simple assignment: Munch.__str__ = Munch.__repr__. The Munch class will also have a static method Munch.fromYAML(), which loads a Munch out of a YAML string.

Finally, Munch converts easily and recursively to (unmunchify(), Munch.toDict()) and from (munchify(), Munch.fromDict()) a normal dict, making it easy to cleanly serialize them in other formats.

Default Values

DefaultMunch instances return a specific default value when an attribute is missing from the collection. Like collections.defaultdict, the first argument is the value to use for missing keys:

>>> from munch import DefaultMunch
>>> undefined = object()
>>> b = DefaultMunch(undefined, {'hello': 'world!'})
>>> b.hello
'world!'
>>> b.foo is undefined
True

DefaultMunch.fromDict() also takes the default argument:

>>> undefined = object()
>>> b = DefaultMunch.fromDict({'recursively': {'nested': 'value'}}, undefined)
>>> b.recursively.nested == 'value'
True
>>> b.recursively.foo is undefined
True

Or you can use DefaultFactoryMunch to specify a factory for generating missing attributes. The first argument is the factory:

>>> from munch import DefaultFactoryMunch
>>> b = DefaultFactoryMunch(list, {'hello': 'world!'})
>>> b.hello
'world!'
>>> b.foo
[]
>>> b.bar.append('hello')
>>> b.bar
['hello']

Miscellaneous

• It is safe to import * from this module. You'll get: Munch, DefaultMunch, DefaultFactoryMunch, munchify and unmunchify.
• Ample Tests. Just run pip install tox && tox from the project root.

Feedback

Open a ticket / fork the project on GitHub.