pydicti
Installation
You can install the newest version of pydicti from PyPI:
pip install pydicti
Alternatively, you can just take the file pydicti.py
and redistribute
it with your application.
Overview
-
class dicti
: default case insensitive dictionary type -
class odicti
: ordered case insensitive dictionary type -
def build_dicti
: create a case insensitive dictionary class -
def Dicti
: create a case insensitive copy of a dictionary
dicti
Objects of type dicti
are dictionaries that feature case insensitive
item access:
>>> d = dicti(Hello='foo', world='bar')
>>> d['heLLO']
'foo'
>>> 'WOrld' in d
True
Internally however, the keys retain their original case:
>>> sorted(d.keys())
['Hello', 'world']
odicti
The type odicti
instanciates order-preserving case insensitive
dictionaries:
>>> odicti(zip('abc', range(3)))
Dicti(OrderedDict([('a', 0), ('b', 1), ('c', 2)]))
build_dicti
With build_dicti
you can create custom case insensitive dictionaries.
This function is what is used to create the pydicti.dicti
and
pydicti.odicti
types. Note that calling build_dicti
several times
with the same argument will result in identical types:
>>> build_dicti(dict) is dicti
True
>>> build_dicti(OrderedDict) is odicti
True
build_dicti
uses subclassing to inherit the semantics of the given base
dictionary type:
>>> issubclass(odicti, OrderedDict)
True
Dicti
The function Dicti
is convenient for creating case insensitive
copies of dictionary instances:
>>> o = OrderedDict(zip('abcdefg', range(7)))
>>> oi = Dicti(o)
>>> type(oi) is odicti
True
JSON
The subclassing approach allows to plug your dictionary instance into
places where typechecking with isinstance
is used, like in the json
module:
>>> import json
>>> d == json.loads(json.dumps(d), object_hook=dicti)
True
You can use json.loads(s, object_pairs_hook=odicti)
to
deserialize ordered dictionaries.
Pitfalls
The equality comparison tries preserves the semantics of the base type as well as reflexitivity. This has impact on the transitivity of the comparison operator:
>>> i = dicti(oi)
>>> roi = odicti(reversed(list(oi.items())))
>>> roi == i and i == oi
True
>>> oi != roi and roi != oi # NOT transitive!
True
>>> oi == i and i == oi # reflexive
True
The coercion rules in python allow this to work pretty well when performing comparisons between types that are subclasses of each other. Be careful otherwise, however.
License
Copyright © 2013 Thomas Gläßle <t_glaessle@gmx.de>
This work is free. You can redistribute it and/or modify it under the terms of the Do What The Fuck You Want To Public License, Version 2, as published by Sam Hocevar. See the COPYING file for more details.
This program is free software. It comes without any warranty, to the extent permitted by applicable law.