natsort-rs

🚀 A blazing fast natural sorting library for Python written in Rust 🦀

Installation

pip install natsort-rs

Usage

from natsort_rs import natsort

Sort a list of strings

items = ['item 1', 'item 10', 'item 3']
print(natsort(items))  
# ['item 1', 'item 3', 'item 10']

Sort case insensitively

items = ['Item 1', 'Item 3', 'item 2']
print(natsort(items, ignore_case=True))
# ['Item 1', 'item 2', 'Item 3']

Sort complex objects based on property

items = [
    {'name': 'item 1', 'id': 1},
    {'name': 'item 3', 'id': 3},
    {'name': 'item 2', 'id': 2}
]
print(natsort(items, key=lambda d: d['name']))
# [{'name': 'item 1', 'id': 1}, {'name': 'item 2', 'id': 2}, {'name': 'item 3', 'id': 3}]

Type-safe sorting

The return type is inferred based on the input list type, so no casting is needed:

items: list[str] = ['item 1', 'item 10', 'item 3']
result = natsort(items)
# result is list[str]

items_int: list[int] = [10, 3, 1]
result_int = natsort(items_int)
# result_int is list[int]

Return the sorting indices

This can be helpful if you only want to get the sorted indices returned, that makes the performance-critical part useful for custom sorting use cases:

items = ['item 1', 'item 10', 'item 3']
print(natsort(items, return_indices=True))  
# [0, 2, 1]

Benchmark

No. of items	Duration natsort [s]	Duration natsort-rs [s]	Relative speedup
10	0.00006	0.00000	16.8
100	0.00094	0.00002	44.3
1000	0.00281	0.00022	12.7
10000	0.02835	0.00262	10.8
100000	0.29712	0.03334	8.9
1000000	3.31207	0.45333	7.3

Execute benchmark.py to reproduce the results.

Development

Local build

To build and test the package locally using uv:

uv run maturin develop --release

Running benchmarks

To run benchmarks:

uv run benchmark.py

This will compare the performance of natsort-rs against the pure Python natsort library and display results in a table format.

Run tests

uv run -m unittest discover tests

Credits

This Python module is build on top of the natord crate and inspired by natsort.

License

MIT License