aadict 0.2.0

An auto-attribute dict (and a couple of other useful dict functions)

An aadict is a python dict sub-class that allows attribute-style access to dict items, e.g. d.foo is equivalent to d['foo']. aadict also provides a few other helpful methods, such as pick and omit methods. Also, an aadict is more call chaining friendly (e.g. methods such as update return self) and is pickle’able.

Project

• Homepage: https://github.com/metagriffin/aadict

• Bugs: https://github.com/metagriffin/aadict/issues

TL;DR

Install:

$ pip install aadict

Use:

from aadict import aadict, pick, omit

# attribute access
d = aadict(foo='bar', zig=87)
assert d.foo == d['foo'] == 'bar'

# helper functions and methods
assert pick(d, 'foo') == d.pick('foo') == {'foo': 'bar'}
assert omit(d, 'foo') == d.omit('foo') == {'zig': 87}

# method chaining
d2 = aadict(x='y').update(d).omit('zig')
assert d2.x == 'y' and d2.foo == 'bar' and d2.zig is None

# prefix extraction
d = {'foo.zig': 'bar', 'foo.zag': 87, 'zig': 'zog'}
assert pick(d, prefix='foo.')        == {'zig': 'bar', 'zag': 87}
assert pick(d, 'zig', prefix='foo.') == {'zig': 'bar'}

Details

The aadict module provides the following functionality:

aadict

An aadict object is basically identical to a dict object, with the exception that attributes, if not reserved for other purposes, map to the dict’s items. For example, if a dict d has an item 'foo', then a request for d.foo will return that item lookup. aadicts also have several helper methods, for example aadict.pick. If a dict item is store by that name, then the attribute access does not work: you need to reference it by item lookup, i.e. d['pick']. The helper methods are:

• aadict.pick instance method:

  Returns a new aadict, reduced to only include the specified keys. Example:

  from aadict import aadict
  d = aadict(foo='bar', zig=87, zag=['a', 'b'])
  assert d.pick('foo', 'zag') == {'foo': 'bar', 'zag': ['a', 'b']}

• aadict.omit instance method:

  Identical to the aadict.pick method, but returns the complement, i.e. all of those keys that are not specified. Example:

  from aadict import aadict
  d = aadict(foo='bar', zig=87, zag=['a', 'b'])
  assert d.omit('foo', 'zag') == {'zig': 87}

• aadict.d2ar class method:

  Recursively converts the supplied dict to an aadict, including all sub-list and sub-dict types. Due to being recursive, but only copying dict-types, this is effectively a hybrid of a shallow and a deep clone. Example:

  from aadict import aadict
  d = aadict.d2ar(dict(foo=dict(bar='zig')))
  assert d.foo.bar == 'zig'

  Without the recursive walking, the .bar attribute syntax would yield an AttributeError exception because d.foo would reference a dict type, not an aadict.

• aadict.d2a class method:

  Converts the supplied dict to an aadict. Example:

  from aadict import aadict
  d = aadict.d2a(dict(foo='bar'))
  assert d.foo == d['foo'] == 'bar'

  Note that this is identical to just using the constructor, but is provided as a symmetry to the aadict.d2ar class method, e.g.:

  from aadict import aadict
  d = aadict(dict(foo='bar'))
  assert d.foo == d['foo'] == 'bar'

pick

A more general-purpose version of the aadict.pick method that can work on any dict type and has a couple of other features. Note that pick will aggressively return a valid dict, regardless of the supplied value – i.e. if None is given as a source, an empty dict is returned. Furthermore, pick also has the following additional functionality via keyword parameters:

• dict:

  Specifies the class type that should be returned, which defaults to the standard python dict type. Example:

  from aadict import pick
  d = pick(dict(foo='bar', zig='zag'), 'foo', dict=aadict)
  assert d == {'foo': 'bar'}
  assert d.foo == 'bar'
  assert isinstance(d, aadict)

• prefix:

  Specifies that only keywords that start with the specified string will be returned (and also filtered for the specified keys), with the prefix stripped from the keys. If no keys are specified, this will simply return only the keys with the specified prefix. Example:

  from aadict import pick
  d = {'foo.zig': 'bar', 'foo.zag': 87, 'zig': 'zog'}
  d2 = pick(d, 'zig', prefix='foo.')
  d3 = pick(d, prefix='foo.')
  assert d2 == {'zig': 'bar'}
  assert d3 == {'zig': 'bar', 'zag': 87}

omit

Identical to the pick function, but returns the compliment. Example:

from aadict import aadict, omit
d = {'foo.zig': 'bar', 'foo.zag': 87, 'zig': 'zog'}
d2 = omit(d, 'zig', prefix='foo.', dict=aadict)
assert d2 == {'zag': 87}
assert d2.zag == 87