orderly-set

library5.5.0pypypi✓ verified 24d ago

Orderly Set is a Python package providing several implementations of ordered set data structures, including `OrderlySet`, `StableSet`, `StableSetEq`, `OrderedSet`, and `RoughMaxSizeSet`. These implementations combine the uniqueness of a set with the order-preserving characteristics of a list or sequence, offering various performance trade-offs for operations such as insertion, deletion, membership testing, and index lookups. The library is actively maintained, with its current version being 5.5.0, and receives regular updates as evidenced by its GitHub release history.

data serialization

pip install orderly-set

github ↗package ↗

INSTALL

IMPORT

SIG · ORDERLY-SET

orderly-set

datapythonv5.5.0

Install

1.5s avg

Import

13ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v5.5.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.014s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.5s · import 0.012s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

OrderedSet

✓ from orderly_set import OrderedSet

✗ from orderedset import OrderedSet

Beware of other 'ordered set' libraries on PyPI with similar names but different import paths and implementations.

StableSet

✓ from orderly_set import StableSet

RoughMaxSizeSet

✓ from orderly_set import RoughMaxSizeSet

OrderlySet

✓ from orderly_set import OrderlySet

Note the capitalization: `OrderlySet` is a specific class within the `orderly_set` package, distinct from `OrderedSet`.

This quickstart demonstrates the creation and basic operations of `OrderedSet` and `StableSet`. `OrderedSet` acts like a hybrid of a list and a set, preserving insertion order with efficient index lookup but O(N) deletion. `StableSet` provides fast O(1) insertion, deletion, and membership testing, but O(N) index lookup.

from orderly_set import OrderedSet, StableSet # Using OrderedSet letters = OrderedSet('abracadabra') print(f"OrderedSet: {letters}") # Expected: OrderedSet(['a', 'b', 'r', 'c', 'd']) print(f"'r' in letters: {'r' in letters}") print(f"Index of 'r': {letters.index('r')}") print(f"Item at index 2: {letters[2]}") letters.add('x') print(f"After adding 'x': {letters}") # Using StableSet (different performance characteristics) stable_items = StableSet([1, 5, 2, 5, 3]) print(f"StableSet: {stable_items}") # Expected: StableSet({1, 5, 2, 3}) stable_items.add(4) print(f"After adding 4: {stable_items}")

Debug

Known issues

breakingVersion 5.4.0 changed behavior for accessing multiple items, switching from a singular `index` method to `indexes` for iterable input. Code using `index` for multiple items may break.

fix

Review calls to `.index()` when attempting to retrieve multiple item indices. The documentation (or source) suggests `__getitem__()` and `index()` methods were extended to accept iterables for 'fancy indexing'.

affects: >=5.4.0

gotchaThere are several 'ordered set' libraries on PyPI (e.g., `orderedset` by simonpercivall, `ordered-set` by rspeer). Ensure you are importing from `orderly_set` as `from orderly_set import ...` to use this specific library.

fix

Always use `from orderly_set import [ClassName]` for `orderly-set`. If you intend to use a different library, verify its specific import path.

affects: All

gotchaThe `OrderedSet` class within `orderly-set` has O(N) deletion performance, which can be a bottleneck for applications with frequent deletions on large sets.

fix

For deletion-heavy workloads where insertion order must be maintained, consider `StableSet` which offers O(1) deletion, or evaluate if a standard `set` (unordered) or Python's built-in `dict` keys (ordered since 3.7 but without list-like indexing) might be more suitable.

affects: All

gotchaThe `StableSet` class within `orderly-set` has O(N) index lookup performance.

fix

If frequent lookups by index are critical, `OrderedSet` offers O(1) index lookup. Choose the implementation (`OrderedSet`, `StableSet`, etc.) that best fits your performance requirements for specific operations.

affects: All

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'orderly_set'

The 'orderly-set' package is either not installed, or there is a typo in the import statement.

fix

Ensure the package is installed using `pip install orderly-set` and the import statement is `from orderly_set import OrderlySet` (or other classes like `OrderedSet`).

from ordered_set import OrderedSet

This is a common wrong import pattern because there is another, similarly named package called 'ordered-set'. If 'orderly-set' is installed, this import will fail.

fix

If you intend to use the `orderly-set` library, change the import to `from orderly_set import OrderedSet` (or the specific class you need from 'orderly_set'). If you intend to use the 'ordered-set' library, install it with `pip install ordered-set`.

AttributeError: 'OrderlySet' object has no attribute 'items'

Users sometimes confuse `OrderlySet` (or other ordered set implementations within the library) with Python's built-in `dict` type and attempt to call dictionary-specific methods like `items()` on it. An `OrderlySet` is a set-like object, not a dictionary.

fix

Access elements directly by iterating over the set or by using set-specific methods. If you need key-value pairs, consider using a dictionary or a custom class that wraps both `OrderlySet` and a dictionary.

AttributeError: 'OrderedSet' object has no attribute 'append'

Users might treat an `OrderedSet` (or other ordered set implementations within the library) like a Python `list` and try to use list-specific methods such as `append()`. While `OrderedSet` maintains order, it is fundamentally a set and does not support list modification methods.

fix

Use set-specific methods like `.add()` for adding elements or convert the set to a list if you require list operations. Keep in mind that converting to a list will lose the uniqueness property if you modify the list and convert back to a set.

Upgrade

Version history

5.5.0latest on PyPI · released Jul 10, 2025

Audit

Dependencies

No dependency data recorded yet.

Agent activity

5 hits · last 30 days

node

Resources

githubhttps://github.com/seperman/orderly-set ↗

packagehttps://pypi.org/project/orderly-set/ ↗