ncw 0.2.0

Nested collections wrapper

ncw

Nested collections wrapper

Classes to access and/or modify data in nested collections, i.e. possibly deep nested dicts or lists of str, int, float, bool, or None.

Installation

Install from PyPI

pip install ncw

Example Usage

The Structure class prevents accidental changes to the underlying data structure by preventing direct access. All returned substructures are deep copies of the internally stored substructures.

The MutableStructure class allows changes (ie. deletions and updates) to the underlying data structure, and returns the internally stored substructures themselves.

Please note that both classes make a deep copy of the data structure at initialization time (thus preventing accidental changes to the original data through the instance).

>>> serialized = '{"herbs": {"common": ["basil", "oregano", "parsley", "thyme"], "disputed": ["anise", "coriander"]}}'
>>>
>>> import json
>>> from ncw import Structure, MutableStructure
>>>
>>> readonly = Structure.from_json_string(serialized)
>>> readonly["herbs"]
{'common': ['basil', 'oregano', 'parsley', 'thyme'], 'disputed': ['anise', 'coriander']}
>>> readonly["herbs.common"]
['basil', 'oregano', 'parsley', 'thyme']
>>> readonly["herbs", "common"]
['basil', 'oregano', 'parsley', 'thyme']
>>> readonly["herbs", "common", 1]
'oregano'
>>> readonly["herbs.common.1"]
'oregano'
>>> readonly["herbs.common.1"] = "marjoram"
Traceback (most recent call last):
  File "<python-input-9>", line 1, in <module>
    readonly["herbs.common.1"] = "marjoram"
    ~~~~~~~~^^^^^^^^^^^^^^^^^^
TypeError: 'Structure' object does not support item assignment
>>>
>>> original_data = json.loads(serialized)
>>> writable = MutableStructure(original_data)
>>> writable.data == original_data
True
>>> writable.data is original_data
False
>>> writable["herbs.common.1"]
'oregano'
>>> writable["herbs.common.1"] = "marjoram"
>>> del writable["herbs", "common", 2]
>>> writable["herbs.common"]
['basil', 'marjoram', 'thyme']
>>>