betterdicts 0.3.1

Better dictionary types for Python.

betterdicts

betterdict

from betterdicts import betterdict

Works just like a dict, but has some extra useful methods:

• invert()

  Inverts a mapping, turning values into keys and vice-versa.

• collate(it, type=list)

  Collects repeated keys into sets or lists depending on the type argument.

• filter(keys=None, values=None)

  Filters keys, values, or both.

• map(keys=None, values=None)

  Map keys, values, or both.

jsdict, njsdict, rjsdict

from betterdicts import jsdict, njsdict, rjsdict

These are betterdicts but works like JavaScript object, where keys and attributes are the same. This is accomplished with zero overhead.

These can be very convenient when working with parameters, configuration, settings, or the like, where the obj['key'] or obj.get('key') access method feels a bit overly verbose for the simple task at hand.

number_dict

Acts like a collections.Counter() with arithmetic support like a number.

>>> q = number_dict(range(5))
>>> q
{0: 1, 1: 1, 2: 1, 3: 1, 4: 1}
>>> q[1] += 5
>>> q[4] += 1
>>> q[9]
0
>>> q[9] = 9
>>> (q+1)**2
{0: 4, 1: 49, 2: 4, 3: 4, 4: 9, 9: 100}
>>> 1 / q
{0: 1.0, 1: 0.16666666666666666, 2: 1.0, 3: 1.0, 4: 0.5, 9: 0.1111111111111111}

persistent_dict

The simplest possible persistent state exposed as a dict.

This is for when you need something really simple to store some flat data between script invocations, without the extra management of databases or file formats or the like.

Any change made directly to the dictionary[^1] causes it to save itself to disk as a pickle file. Whenever an instance is created of this dictionary it will load the same file.

The file defaults to cache.pickle in the current working directory, but can be specified as a parameter with persistent_dict(cache_file=<FILENAME>).

[^1]: "deep" changes like to objects stored in the dictionary are not tracked