dict扩展munch，支持yaml文件

安装：pip install munch

用法参考：https://github.com/Infinidat/munch

Munch is a dictionary that supports attribute-style access, a la JavaScript.意思是支持"a.b"的写法获取属性值

In []: from munch import Munch

In []: b=Munch()

In []: b.hello='world'

In []: b
Out[]: Munch({'hello': 'world'})

In []: b.hello
Out[]: 'world'

In []: b.hello+="!"

In []: b
Out[]: Munch({'hello': 'world!'})

In []: b.fool=Munch(lol=True)

In []: b
Out[]: Munch({'hello': 'world!', 'fool': Munch({'lol': True})})

In []: b.fool
Out[]: Munch({'lol': True})

In []: b.fool.lol
Out[]: True

In []: b['fool']
Out[]: Munch({'lol': True})

In []: b['fool']['lol']
Out[]: True

In []: b['fool'].lol
Out[]: True

自然也是支持字典的各种用法：

In []: b.keys()
Out[]: dict_keys(['hello', 'fool'])

In []: b.update({'ponies':'are prettty!'},hello=)

In []: b
Out[]: Munch({'hello': , 'ponies': 'are prettty!', 'fool': Munch({'lol': True})})

In []: print(repr(b))
Munch({'hello': , 'ponies': 'are prettty!', 'fool': Munch({'lol': True})})

In []: [ (k,b[k]) for k in b ]
Out[]: [('hello', ), ('ponies', 'are prettty!'), ('fool', Munch({'lol': True}))]

In []: "The {knights} who say {ni}!".format(**Munch(knights='lolcats', ni='can haz'))
Out[]: 'The lolcats who say can haz!'

In []: "The {knights} who say {ni}!".format(**{'knights':'test','ni':'wo'})
Out[]: 'The test who say wo!'

使用json和yaml实现序列化：

In []: b = Munch(foo=Munch(lol=True), hello=, ponies='are pretty!')

In []: import json

In []: json.dumps(b)
Out[]: '{"hello": 42, "ponies": "are pretty!", "foo": {"lol": true}}'

In []: import yaml

In []: yaml.dump(b)
Out[]: '!munch.Munch\nfoo: !munch.Munch {lol: true}\nhello: 42\nponies: are pretty!\n'

In []: yaml.safe_dump(b)
Out[]: 'foo: {lol: true}\nhello: 42\nponies: are pretty!\n'

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:

>>> 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:

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