Extra Python Collections - bags (multisets) and setlists (ordered sets)

2.0.2 · active · verified Sat Apr 11

collections_extended is a pure Python module with no dependencies providing various extended collection types. It includes a bag (multiset) class, a setlist (ordered set / unique list) class, a bijection, a RangeMap, and an IndexedDict. It also offers frozen (hashable) variants of bags and setlists. The current version, 2.0.2, maintains an active development status with regular updates and is compatible with Python 3.7+.

Warnings

breaking Version 2.0.0 dropped support for Python 2.7, 3.4, and 3.5. Ensure your environment is Python 3.6 or later for v2.x.
Fix: Upgrade Python to 3.7+ or pin collections-extended to a 1.x version if Python 2.7/3.4/3.5 support is required.
breaking When multiplying `bag` objects, the behavior changed in v2.0.0. It now produces a cartesian product as a tuple, rather than adding elements.
Fix: Review code that uses `bag` multiplication (`*`) and adjust logic if the previous 'addition' behavior was expected. The new behavior is a cartesian product, yielding tuples.
breaking As of v2.0.0, `bags` no longer inherit from `Set`, meaning they cannot be compared for equality directly with `Set` objects.
Fix: If comparing `bag` instances with `set` instances, explicit conversion (e.g., `set(my_bag) == my_set`) or a different comparison logic may be necessary.
breaking Internal base classes `_basebag` and `_basesetlist` were renamed to `Bag` and `SetList` respectively and are now exposed in v2.0.0.
Fix: Update any direct imports or references to `_basebag` or `_basesetlist` to use `Bag` or `SetList`.
gotcha Calling `setlist.insert(index, element)` will raise a `ValueError` if the `element` is already present in the `setlist`.
Fix: Check for element existence (e.g., `if element not in my_setlist: my_setlist.insert(...)`) or handle the `ValueError` if duplicate insertion is attempted.
gotcha `setlist` objects are not comparable using ordering operators (`<`, `>`, `<=`, `>=`) due to the ambiguity between set comparison and order-based comparison. Equality (`==`, `!=`) still works.
Fix: If order-sensitive comparison is needed, convert `setlist` to a `list`. For set-based comparison, convert to a `set`.

Install

pip install collections-extended Install with pip

Imports

bag
```
from collections_extended import bag
```

setlist

from collections_extended import setlist

IndexedDict

from collections_extended import IndexedDict

RangeMap

from collections_extended import RangeMap

bijection

from collections_extended import bijection

frozenbag

from collections_extended import frozenbag

frozensetlist

from collections_extended import frozensetlist

Quickstart

Demonstrates basic usage of `bag`, `setlist`, `IndexedDict`, and `RangeMap` from `collections-extended`.

from collections_extended import bag, setlist, IndexedDict, RangeMap
from datetime import date

# Example with bag (multiset)
b = bag('abracadabra')
print(f"Bag: {b}, Count of 'a': {b.count('a')}")
b.remove('a')
print(f"Bag after removing 'a': {b}, Count of 'a': {b.count('a')}")

# Example with setlist (ordered set)
sl = setlist('abracadabra')
print(f"Setlist: {sl}, element at index 3: {sl[3]}")
try:
    sl.insert(1, 'd')
except ValueError as e:
    print(f"Attempted to insert duplicate into setlist: {e}")

# Example with IndexedDict
idict = IndexedDict({'a': 1, 'b': 2, 'c': 3})
print(f"IndexedDict: {idict}, value at index 1: {idict.iloc[1]}")

# Example with RangeMap
version_map = RangeMap()
version_map[date(2017, 10, 20): date(2017, 10, 27)] = '0.10.1'
version_map[date(2017, 10, 27):] = '1.0.0'
print(f"Version for 2017-10-24: {version_map[date(2017, 10, 24)]}")

view raw JSON →