Rustiter

Rust-inspired iterator utilities for Python. This library implements most of the functions from the Rust Iterator trait.

Why

I'm a big fan of chaining function calls, but Python's functional programming tools can be cumbersome. No one really wants to use the built-in map, filter, and reduce functions.

I previously experimented with simpleufcs, which allows for chainable function calls in Python.

This library offers an alternative: while it doesn't provide full UFCS (Uniform Function Call Syntax), it performs slightly better and brings many useful functions from Rust’s iterator design, such as take, flat_map, and more. If you're familiar with Rust and not too concerned about performance, you'll likely enjoy using this.

Installation

pip install rustiter

Example

Here are some commonly used functions:

from rustiter import rter
ret = (
    rter(range(10))
    .filter(lambda x: x % 2 == 0)
    .map(lambda x: x + 1)
    .take(3)
    .collect()
)
assert ret == [1, 3, 5]
assert rter(range(10)).reduce(lambda x, y: x + y, 0) == 45

Additional Information: Every function includes a doctest to demonstrate its usage.

Mutability

The mutability of Python's iterator is not ideal. Therefore, I marked the mutability of the functions as follows:

• [Mut]: The iterator may be modified after this operation. If there's not a retains = ..., the rest elements is undefined.
• [UnMut]: The iterator will not be modified.
• [Consume]: The iterator may be consumed after this operation. Note that this does not mean the iterator will become empty; there may still be elements in it. This means that you should not use this iterator again.

benchmark

Windows 11, python 3.12.7