refdict 3.3.0

Using string as chain keys to realize chain access and reference access of dict in python

refdict

Usage

• Using string as chain keys to realize chain access(including dict/list/tuple/str).
• String can perform as a reference of another item.

Install

pip install refdict

Features

• Using refdict just like using dict/list/tuple/str.
  • Methods of built-in types: refdict({}).keys() or refdict([]).append(123).
  • Iteration and containment check: for x in refdict([1, 2, 3]).
  • Slice and slice assignment: refdict([1, 2, 3])[:] => [1, 2, 3].
  • ...
• Chain accessing members using a string.
  • refdict({'1':{'1':{'1':{'1':'1'}}}})['1.1.1.1'] => 1.
• Using reference string to reference another item.

Description

Use reference prefix to turn a string into a reference of another item. The default reference prefix is @. Reference prefix can be changed by the parameter refPrefix of the constructor of refdict.

The [] operator can be used for chain access and reference access. The separator of keys is . by default, and it can be changed by the parameter separator of the constructor.

Here is an example:

data = {
	'player': {
		'name': 'DiscreteTom',
		'items': [
			'@potion.red'
		],
		'weapon': '@sword',
		'attack': '@player.weapon.attack',
		'me': '@player'
	},
	'potion': {
		'red': 'restore your health by 20%',
	},
	'sword': {
		'attack': 123
	},
}
rd = refdict(data)
print(rd['player.items.0']) # => restore your health by 20%
print(rd['player.attack']) # => 123
print(rd['player.items.:']) # => ['@potion.red']
print(rd.text('player.attack')) # => @player.weapon.attack
print('player.weapon' in rd) # => True

Warnings

Recursive references like item: @item will cause infinite loop, including indirect reference.

data = {
	'item': '@item', # => infinite loop!
	'wrapper': {
		'item': '@wrapper.item' # => infinite loop!
	},
	'a': '@b' # => infinite loop!
	'b': '@a' # => infinite loop!
}

FAQ

• Q - Why I can't access the first item of list/tuple/str using [1]?
  • A - Of course you should use [0] to access the first item, just like using list/tuple/str. It's a little bit counter-intuitive but reasonable.
• Q - Why I got KeyError when using rd['key1.key2']['key3.key4']?
  • The first [] operator will return a non-refdict object, so you can't use chain keys in the following []. To get a sub-refdict, you should use () operator, which means you should use rd('key1.key2')['key3.key4'].