python-box 3.4.2

Advanced Python dictionaries with dot notation access

Python dictionaries with advanced dot notation access.

from box import Box

movie_data = {
  "movies": {
    "Spaceballs": {
      "imdb stars": 7.1,
      "rating": "PG",
      "length": 96,
      "director": "Mel Brooks",
      "stars": [{"name": "Mel Brooks", "imdb": "nm0000316", "role": "President Skroob"},
                {"name": "John Candy","imdb": "nm0001006", "role": "Barf"},
                {"name": "Rick Moranis", "imdb": "nm0001548", "role": "Dark Helmet"}
      ]
    },
    "Robin Hood: Men in Tights": {
      "imdb stars": 6.7,
      "rating": "PG-13",
      "length": 104,
      "director": "Mel Brooks",
      "stars": [
                {"name": "Cary Elwes", "imdb": "nm0000144", "role": "Robin Hood"},
                {"name": "Richard Lewis", "imdb": "nm0507659", "role": "Prince John"},
                {"name": "Roger Rees", "imdb": "nm0715953", "role": "Sheriff of Rottingham"},
                {"name": "Amy Yasbeck", "imdb": "nm0001865", "role": "Marian"}
      ]
    }
  }
}

# Box is a conversion_box by default, pass in `conversion_box=False` to disable that behavior
movie_box = Box(movie_data)


movie_box.movies.Robin_Hood_Men_in_Tights.imdb_stars
# 6.7

movie_box.movies.Spaceballs.stars[0].name
# 'Mel Brooks'

# All new dict and lists added to a Box or BoxList object are converted
movie_box.movies.Spaceballs.stars.append({"name": "Bill Pullman", "imdb": "nm0000597", "role": "Lone Starr"})
movie_box.movies.Spaceballs.stars[-1].role
# 'Lone Starr'

Install

pip install python-box

Box is tested on python 2.7 and 3.4+. If it does not install with this command, please open a github issue with the error you are experiencing!

If you want to be able to use the to_yaml functionality make sure to install PyYAML or ruamel.yaml as well.

Overview

Box is designed to be an easy drop in transparently replacements for dictionaries, thanks to Python’s duck typing capabilities, which adds dot notation access. Any sub dictionaries or ones set after initiation will be automatically converted to a Box object. You can always run .to_dict() on it to return the object and all sub objects back into a regular dictionary.

movie_box.movies.Spaceballs.to_dict()
{'director': 'Mel Brooks',
 'imdb stars': 7.1,
 'length': 96,
 'personal thoughts': 'On second thought, it was hilarious!',
 'rating': 'PG',
 'stars': [{'imdb': 'nm0000316', 'name': 'Mel Brooks', 'role': 'President Skroob'},
           {'imdb': 'nm0001006', 'name': 'John Candy', 'role': 'Barf'},
           {'imdb': 'nm0001548', 'name': 'Rick Moranis', 'role': 'Dark Helmet'},
           {'imdb': 'nm0000597', 'name': 'Bill Pullman', 'role': 'Lone Starr'}]}

Box version 3 (and greater) now do sub box creation upon lookup, which means it is only referencing the original dict objects until they are looked up or modified.

a = {"a": {"b": {"c": {}}}}
a_box = Box(a)
a_box
# <Box: {'a': {'b': {'c': {}}}}>

a["a"]["b"]["d"] = "2"

a_box
# <Box: {'a': {'b': {'c': {}, 'd': '2'}}}>

So if you plan to keep the original dict around, make sure to box_it_up or do a deepcopy first.

safe_box = Box(a, box_it_up=True)
a["a"]["b"]["d"] = "2"

safe_box
# <Box: {'a': {'b': {'c': {}}}}>

Limitations

Box is a subclass of dict and as such, certain keys cannot be accessed via dot notation. This is because names such as keys and pop have already been declared as methods, so Box cannot use it’s special sauce to overwrite them. However it is still possible to have items with those names in the Box and access them like a normal dictionary, such as my_box[‘keys’].

This is as designed, and will not be changed.

The non-magic methods that exist in a Box are: box_it_up, clear, copy, from_json, fromkeys, get, items, keys, pop, popitem, setdefault, to_dict, to_json, update, values. To view an entire list of what cannot be accessed via dot notation, run the command dir(Box()).

Box

Box can be instantiated the same ways as dict.

Box({'data': 2, 'count': 5})
Box(data=2, count=5)
Box({'data': 2, 'count': 1}, count=5)
Box([('data', 2), ('count', 5)])

# All will create
# <Box: {'data': 2, 'count': 5}>

Box is a subclass of dict which overrides some base functionality to make sure everything stored in the dict can be accessed as an attribute or key value.

small_box = Box({'data': 2, 'count': 5})
small_box.data == small_box['data'] == getattr(small_box, 'data')

All dicts (and lists) added to a Box will be converted on lookup to a Box (or BoxList), allowing for recursive dot notation access.

Box also includes helper functions to transform it back into a dict, as well as into JSON or YAML strings or files.

Conversion Box

By default, Box is now a conversion_box that adds automagic attribute access for keys that could not normally be attributes. It can of course be disabled with the keyword argument conversion_box=False.

movie_box.movies.Spaceballs["personal thoughts"] = "It was a good laugh"
movie_box.movies.Spaceballs.personal_thoughts
# 'It was a good laugh'

movie_box.movies.Spaceballs.personal_thoughts = "On second thought, it was hilarious!"
movie_box.movies.Spaceballs["personal thoughts"]
# 'On second thought, it was hilarious!'

# If a safe attribute matches a key exists, it will not create a new key
movie_box.movies.Spaceballs["personal_thoughts"]
# KeyError: 'personal_thoughts'

Keys are modified in the following steps to make sure they are attribute safe:

1. Convert to string (Will encode as UTF-8 with errors ignored)
2. Replaces any spaces with underscores
3. Remove anything other than ascii letters, numbers or underscores
4. If the first character is an integer, it will prepend a lowercase ‘x’ to it
5. If the string is a built-in that cannot be used, it will prepend a lowercase ‘x’
6. Removes any duplicate underscores

This does not change the case of any of the keys.

bx = Box({"321 Is a terrible Key!": "yes, really"})
bx.x321_Is_a_terrible_Key
# 'yes, really'

These keys are not stored anywhere, and trying to modify them as an attribute will actually modify the underlying regular key’s value.

Warning: duplicate attributes possible

If you have two keys that evaluate to the same attribute, such as “a!b” and “a?b” would become .ab, there is no way to discern between them, only reference or update them via standard dictionary modification.

Frozen Box

Want to show off your box without worrying about others messing it up? Freeze it!

frigid = Box(data={'Python': 'Rocks', 'inferior': ['java', 'cobol']}, frozen_box=True)

frigid.data.Python = "Stinks"
# box.BoxError: Box is frozen

frigid.data.Python
# 'Rocks'

hash(frigid)
# 4021666719083772260

frigid.data.inferior
# ('java', 'cobol')

It’s hashing ability is the same as the humble tuple, it will not be hashable if it has mutable objects. Speaking of tuple, that’s what all the lists becomes now.

Default Box

It’s boxes all the way down. At least, when you specify default_box=True it can be.

empty_box = Box(default_box=True)

empty_box.a.b.c.d.e.f.g
# <Box: {}>

empty_box.a.b.c.d.e.f.g = "h"
empty_box
# <Box: {'a': {'b': {'c': {'d': {'e': {'f': {'g': 'h'}}}}}}}>

Unless you want it to be something else.

evil_box = Box(default_box=True, default_box_attr="Something Something Something Dark Side")

evil_box.not_defined
# 'Something Something Something Dark Side'

# Keep in mind it will no longer be possible to go down multiple levels
evil_box.not_defined.something_else
# AttributeError: 'str' object has no attribute 'something_else'

default_box_attr will first check if it is callable, and will call the object if it is, otherwise it will see if has the copy attribute and will call that, lastly, will just use the provided item as is.

Camel Killer Box

Similar to how conversion box works, allow CamelCaseKeys to be found as snake_case_attributes.

cameled = Box(BadHabit="I just can't stop!", camel_killer_box=True)

cameled.bad_habit
# "I just can't stop!"

Ordered Box

Preserve the order that the keys were entered into the box. The preserved order will be observed while iterating over the box, or calling .keys(), .values() or .items()

box_of_order = Box(ordered_box=True)
box_of_order.c = 1
box_of_order.a = 2
box_of_order.d = 3

box_of_order.keys() == ['c', 'a', 'd']

Keep in mind this will not guarantee order of **kwargs passed to Box, as they are inherently not ordered until Python 3.6.

BoxList

To make sure all items added to lists in the box are also converted, all lists are covered into BoxList. It’s possible to initiate these directly and use them just like a Box.

from box import BoxList

my_boxlist = BoxList({'item': x} for x in range(10))
#  <BoxList: [<Box: {'item': 0}>, <Box: {'item': 1}>, ...

my_boxlist[5].item
# 5

to_list

Transform a BoxList and all components back into regular list and dict items.

my_boxlist.to_list()
# [{'item': 0},
#  {'item': 1},
#  ...

SBox

Shorthand Box, aka SBox for short(hand), has the properties json, yaml and dict for faster access than the regular to_dict() and so on.

from box import SBox

sb = SBox(test=True)
sb.json
# '{"test": true}'

Note that in this case, json has no default indent, unlike to_json.

ConfigBox

A Box with additional handling of string manipulation generally found in config files.

test_config.ini

[General]
example=A regular string

[Examples]
my_bool=yes
anint=234
exampleList=234,123,234,543
floatly=4.4

With the combination of reusables and ConfigBox you can easily read python config values into python types. It supports list, bool, int and float.

import reusables
from box import ConfigBox

config = ConfigBox(reusables.config_dict("test_config.ini"))
# <ConfigBox: {'General': {'example': 'A regular string'},
# 'Examples': {'my_bool': 'yes', 'anint': '234', 'examplelist': '234,123,234,543', 'floatly': '4.4'}}>

config.Examples.list('examplelist')
# ['234', '123', '234', '543']

config.Examples.float('floatly')
# 4.4

BoxObject

An object wrapper with a Box for a __dict__.

import requests
from box import BoxObject

def get_html(session, url, *args, **kwargs):
    response = session.get(url, *args, **kwargs)
    text = response.text
    response_meta = response.__dict__
    for key in tuple(filter(lambda k: k.startswith('_'), response_meta)):
        response_meta.pop(key)
    return BoxObject(text, response_meta, frozen_box=True)

box_url = 'https://raw.githubusercontent.com/cdgriffith/Box/master/box.py'
with requests.Session() as session:
    box_source = get_html(session, box_url)

box_source.url
# https://raw.githubusercontent.com/cdgriffith/Box/master/box.py

box_source.status_code
# 200

box_source.raw.reason
# OK

BoxObject act just like objects but they secretly carry around a Box with them to store attributes. BoxObject are built off of wrapt.ObjectProxy which can wrap almost any python object. They protect their wrapped objects storing them in the __wrapped__ attribute and keeping the original __dict__ in __wrapped__.__dict__.

See the Wrapt Documentation, specifically the section on ObjectProxy, for more information.

License

MIT License, Copyright (c) 2017-2018 Chris Griffith. See LICENSE file.