python-box 4.2.0

Advanced Python dictionaries with dot notation access

Python dictionaries with advanced dot notation access.

from box import Box

movie_box = Box({
    "Robin Hood: Men in Tights": {
        "imdb_stars": 6.7,
        "length": 104,
        "stars": [ {"name": "Cary Elwes", "imdb": "nm0000144", "role": "Robin Hood"},
                   {"name": "Richard Lewis", "imdb": "nm0507659", "role": "Prince John"} ]
    }
})

movie_box.Robin_Hood_Men_in_Tights.imdb_stars
# 6.7

movie_box.Robin_Hood_Men_in_Tights.stars[0].name
# 'Cary Elwes'

Box will automatically make otherwise inaccessible keys (“Robin Hood: Men in Tights”) safe to access as an attribute. You can always pass conversion_box=False to Box to disable that behavior.

Also, all new dict and lists added to a Box or BoxList object are converted automatically.

movie_box.Robin_Hood_Men_in_Tights.stars.append(
     {"name": "Roger Rees", "imdb": "nm0715953", "role": "Sheriff of Rottingham"})

movie_box.Robin_Hood_Men_in_Tights.stars[-1].role
# 'Sheriff of Rottingham'

Install

pip install --upgrade python-box

Box 4 is tested on python 3.6+

If you have any issues please open a github issue with the error you are experiencing!

Overview

Box 4 is out, check out the changes and updates!

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'}]}

Boxes

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.

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.

Common 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, merge_update, values. To view an entire list of what cannot be accessed via dot notation, run the command dir(Box()).

Box’s parameters

Keyword Argument	Default	Description
conversion_box	True	Automagically make keys with spaces attribute accessible
frozen_box	False	Make the box immutable, hashable (if all items are non-mutable)
default_box	False	Act like a recursive default dict
default_box_attr	Box	Can overwrite with a different (non-recursive) default attribute to return
camel_killer_box	False	CamelCaseKeys become attribute accessible like snake case (camel_case_keys)
box_safe_prefix	“x”	Character or prefix to prepend to otherwise invalid attributes
box_duplicates	“ignore”	When conversion duplicates are spotted, either ignore, warn or error
box_intact_types	()	Tuple of objects to preserve and not convert to a Box object
box_recast	None	cast certain keys to a specified type
box_dots	False	Allow access to nested dicts by dots in key names

Box’s functions

Function Name	Description
to_dict	Recursively transform all Box (and BoxList) objects back into a dict (and lists)
to_json	Save Box object as a JSON string or write to a file with the filename parameter
to_yaml	Save Box object as a YAML string or write to a file with the filename parameter
to_toml*	Save Box object as a TOML string or write to a file with the filename parameter
box_it_up	Recursively create all objects into Box and BoxList objects (to front-load operation)
from_json	Classmethod, Create a Box object from a JSON file or string (all Box parameters can be passed)
from_yaml	Classmethod, Create a Box object from a YAML file or string (all Box parameters can be passed)
from_toml*	Classmethod, Create a Box object from a TOML file or string (all Box parameters can be passed)

* Do not work with BoxList, only Box

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: {}>

# BOX 4.1 change, on lookup the sub boxes are created
print(empty_box)
# <Box: {'a': {'b': {'c': {'d': {'e': {'f': {'g': {}}}}}}}}>

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.

4.1 Update: Previous versions had an error when something that evaluated to None would also return a box, such as an empty string or empty list. This behavior has been fixed.

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!"

Box Recast Values

Automatically convert all incoming values of a particular key (at root or any sub box) to a different type.

For example, if you wanted to make sure any field labeled ‘id’ was an integer:

my_box = Box(box_recast={'id': int})

my_box.new_key = {'id': '55', 'example': 'value'}

print(type(my_box.new_key.id))
# 55

If it cannot be converted, it will raise a BoxValueError (catachable with either BoxError or ValueError as well)

my_box = Box(box_recast={'id': int})

my_box.id = 'Harry'

# box.exceptions.BoxValueError: Cannot convert Harry to <class 'int'>

Box Intact Types

Do you not want box to convert lists or tuples or incoming dictionaries for some reasonn? That’s totally fine, we got you covered!

my_box = Box(box_intact_types=[list, tuple])

# Don't automatically convert lists into #BoxList
my_box.new_data = [{'test': 'data'}]

print(type(my_box.new_data))
# <class 'list'>

Box Dots

A new way to traverse the Box!

my_box = Box(box_dots=True)

my_box.incoming = {'new': {'source 1': {'$$$': 'money'}}}

print(my_box['incoming.new.source 1.$$$'])
# money

my_box['incoming.new.source 1.$$$'] = 'spent'
print(my_box)
# {'incoming': {'new': {'source 1': {'$$$': 'spent'}}}}

Be aware, if those sub boxes didn’t exist as planned, a new key with that value would be created instead

del my_box['incoming']
my_box['incoming.new.source 1.$$$'] = 'test'
print(my_box)

# {'incoming.new.source 1.$$$': 'test'}

4.1 Update: Support for traversing box lists as well!

my_box = Box({'data': [ {'rabbit': 'hole'} ] }, box_dots=True)
print(data.data[0].rabbit)
# hole

This does only work for keys that are already strings as of version 4.1.

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

Thoughts

“Awesome time (and finger!) saver.” - Zenlc2000

“no thanks.” - burnbabyburn

“I just prefer plain dictionaries.” - falcolas

Thanks

A huge thank you to everyone that has given features and feedback over the years to Box!

Check out everyone that has contributed.

A special thanks to Python Software Foundation, and PSF-Trademarks Committee, for official approval to use the Python logo on the Box logo!

Also special shout-out to PythonBytes, who featured Box on their podcast.

History

Feb 2014: Inception

Box was first created under the name Namespace in the reusables package. Years of usage and suggestions helped mold it into the largest section of the reusables library.

Mar 2017: Box 1.0

After years of upgrades it became clear it was used more than most other parts of the reusables library of tools. Box become its own package.

Mar 2017: BoxLists

2.0 quickly followed 1.0, adding BoxList to allow for further dot notations while down in lists. Also added the handy to_json and to_yaml functionality.

May 2017: Options

Box 3.0 brought a lot of options to the table for maximum customization. From allowing you to freeze the box or just help you find your attributes when accessing them by dot notation.

Dec 2019: 2.7 EOL

Box 4.0 was made with python 2.x out of mind. Everything from f-strings to type-hinting was added to update the package. The modules grew large enough to separate the different objects into their own files and test files.

License

MIT License, Copyright (c) 2017-2020 Chris Griffith. See LICENSE file.