Dotsi

Dot-accessible, update-aware Python dicts (& lists). Works recursively, like a charm.

Dotsi defines two classes, dotsi.Dict and dotsi.List, which work together to bring JavaScript-like dot-notation to Python dicts (and lists therein).

Installation

pip install dotsi

Alternately, download dotsi.py it into your project directory.

Usage

Let's dive right in:

>>> import dotsi
>>> 
>>> d = dotsi.Dict({"foo": {"bar": "baz"}})     # Basic
>>> d.foo.bar
'baz'
>>> d.users = [{"id": 0, "name": "Alice"}]   # List
>>> d.users[0].name
'Alice'
>>> d.users.append({"id": 1, "name": "Becca"}); # Append
>>> d.users[1].name
'Becca'
>>> d.users += [{"id": 2, "name": "Cathy"}];    # `+=`
>>> d.users[2].name
'Cathy'
>>> d.update({"tasks": [{"id": "a", "text": "Task A"}]});
>>> d.tasks[0].text
'Task A'
>>> d.tasks[0].tags = ["red", "white", "blue"];
>>> d.tasks[0].tags[2];
'blue'
>>> d.tasks[0].pop("tags")                      # `.pop()`
['red', 'white', 'blue']
>>> 
>>> import pprint
>>> pprint.pprint(d)
{'foo': {'bar': 'baz'},
 'tasks': [{'id': 'a', 'text': 'Task A'}],
 'users': [{'id': 0, 'name': 'Alice'},
           {'id': 1, 'name': 'Becca'},
           {'id': 2, 'name': 'Cathy'}]}
>>> 
>>> type(d.users)       # dotsi.Dict (AKA dotsi.DotsiDict)
<class 'dotsi.DotsiList'>
>>> type(d.users[0])    # dotsi.List (AKA dotsi.DotsiList)
<class 'dotsi.DotsiDict'> 
>>> 

In the above example, while we explicitly initialized d as an dotsi.Dict:

• d.users automatically became a dotsi.List.
• d.users[0] automatically became a dotsi.Dict.

Dotsi vs Others

Addict:

At Polydojo, we've been using Addict for quite some time. It's a great library! But it doesn't play well with list-nested (inner) dicts.

>>> import addict
>>> 
>>> d = addict.Dict({"foo": {"bar": "baz"}})
>>> d.foo
{'bar': 'baz'}
>>> d.users = [{"id": 0, "name": "Alice"}]
>>> d.users[0].name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'dict' object has no attribute 'name'
>>> 

EasyDict:

EasyDict is another great library. It works recursively, but doesn't fully support list-nested dict updates.

>>> import easydict
>>> 
>>> d = easydict.EasyDict({"foo": {"bar": "baz"}})
>>> d.foo
{'bar': 'baz'}
>>> d.users = [{"id": 0, "name": "Alice"}]
>>> d.users[0].name
'Alice'
>>> d.users.append({"id": 1, "name": "Becca"});
>>> d.users[1].name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'dict' object has no attribute 'name'
>>> 

Shortcuts

Classes:

• dotsi.Dict is a short alias for dotsi.DotsiDict.
• dotsi.List is a short alias for dotsi.DotsiList.

Functions:

• dotsi.dotsify() calls dotsi.Dict/dotsi.List, as appropriate.
• dotsi.fy() is a short alias for dotsi.dotsify().
• dotsi.mapdotsify() is like the built-in map(), but returns a dotsi.List.
• dotsi.mapfy is a short alias for dotsi.mapdotsify(). (More on this below.)

In most cases, all you need is:

• dotsi.fy(thing), where thing is a dict or list.

Dict-Like Objects

While dotsi.fy() converts objects of type dict to dotsi.Dict, it doesn't touch other dict-like objects, such as those of type collections.OrderedDict or http.cookies.SimpleCookie.

To convert a non-dict, but dict-like object to dotsi.Dict, use dotsi.Dict(.) directly, or use dotsi.fy(dict(.)).

>>> import dotsi
>>> from collections import OrderedDict
>>> 
>>> d = OrderedDict({"foo": {"bar": "baz"}})
>>> d
OrderedDict([('foo', {'bar': 'baz'})])
>>> type(d)
<class 'collections.OrderedDict'>
>>>
>>> x = dotsi.fy(d)
>>> x
OrderedDict([('foo', {'bar': 'baz'})])
>>> type(x)
<class 'collections.OrderedDict'>
>>> 
>>> y = dotsi.Dict(d)
>>> y
{'foo': {'bar': 'baz'}}
>>> type(y)
<class 'dotsi.DotsiDict'>
>>> 
>>> z = dotsi.fy(dict(d))
>>> z
{'foo': {'bar': 'baz'}}
>>> type(z)
<class 'dotsi.DotsiDict'>

Subclasses of dict, such as http.cookie.SimpleCookie, often implement custom behavior, which would be lost on conversion to dotsi.Dict. Thus, automatic conversion shouldn't be implemented.

Quick Plug

Dotsi is built and maintained by the folks at Polydojo, Inc., led by Sumukh Barve. If your team is looking for a simple project management tool, please check out our latest product: BoardBell.com.

List-Like Objects

Like with dicts, dotsi.fy(.) only converts objects of type list to dotsi.List, but doesn't touch other list-like objects or tuples. To convert a non-list, but list-like object to dotsi.List, directly call dotsi.List(.) or use dotsi.fy(list(.))

Identity Function

For non-dict and non-list objects, dotsi.fy(.) is equivalent to the identity function.

Kindly note that from Python3+, the built-in map() produces a non-list iterable. Thus, calling dotsi.fy(map(.)) is equivalent to just map(.). Instead, please use dotsi.List(map(.)).

Mapping Helper

As mapping is a pretty-common use case, we've included dotsi.mapfy(.), which is essentially equivalent to dotsi.List(map(.)). But additionally, with dotsi.mapfy(.), for mapping onto a single sequence, you may pass arguments in either order.

That is, the following lines are equivalent:

• x = dotsi.mapfy(lambda n: {"n": n}, [0, 1, 2])
• x = dotsi.mapfy([0, 1, 2], lambda n: {"n": n})

In either case, x[0].n == 0 will be True.

When mapping onto multiple sequences, dotsi.mapfy(.) expects the same order of arguments as map(.).

Overridden Methods

Excluding magic-methods like .__init__(.) etc., methods overridden by Dotsi are listed below.

dotsi.Dict overrides:

• .update(.)
• .setdefault(.)
• .copy(.)

dotsi.List overrides:

• insert(.)
• append(.)
• extend(.)
• copy(.)

Signatures for all overridden methods should be equivalent (if not exactly identical) to their non-overridden counterparts.

Underscore-Like Helpers

The following helper functions are inspired by their counterparts in Underscore.js.

• dotsi.extend(tgt, *srcs)
• dotsi.defaults(tgt, *srcs)

Note that these helpers don't dotsi.fy() the result. While tgt is updated (and returned), it's type remains unchanged.

Licensing

Copyright (c) 2020 Polydojo, Inc.

Software Licensing:
The software is released "AS IS" under the MIT license, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. Kindly see LICENSE.txt for more details.

No Trademark Rights:
The above software licensing terms do not grant any right in the trademarks, service marks, brand names or logos of Polydojo, Inc.