---
id: llist
version: "0.7.1"
license: MIT
license_treatment: permissive
maintenance: dormant
---

# llist — Linked list data structures for Python

License: permissive · Maintenance: dormant · Downloads: 136.0K/mo

## What it is and what it does

llist is a C extension module that implements linked list data structures—specifically doubly linked lists (dllist) and singly linked lists (sllist)—for CPython. It targets workloads where fast insertion and deletion in the middle of a sequence matter more than random access, offering potential speed advantages over collections.deque or standard Python lists for those specific operations.

The package has no runtime dependencies and is distributed under the MIT license. However, it requires compilation during installation, which means you need a C compiler and CPython development headers. The project is dormant: the last release was in 2021, though the repository remains on GitHub with occasional commits. This age raises questions about compatibility with modern Python versions and whether the performance claims still hold.

Use it for:

- Implementing algorithms that frequently insert or remove elements from the middle of a sequence, such as certain graph or simulation workloads.
- Building data structures like queues or deques where you need efficient bidirectional traversal and modification.
- Performance-critical code where collections.deque is a bottleneck for middle-of-sequence operations.
- Educational purposes to understand linked list behavior and API design in CPython.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides doubly and singly linked list data structures as C extension modules for CPython, optimized for fast insertions and deletions in the middle of sequences.

No, unless you have a specific performance requirement for linked list operations that you've benchmarked against alternatives. The high install friction (C compilation required), dormant maintenance status (last release 2021), and lack of recent updates create risk for modern Python environments. The performance advantage over collections.deque is unverified on current Python versions. Consider collections.deque first unless you have concrete evidence this package solves a real bottleneck.

## Install

pip install llist
uv add llist
poetry add llist

## Installing llist

Before you install: High install friction: this is a C extension that requires compilation. The package is dormant (last release 2021-04-26, 1936 days ago) with no recent maintenance activity, though the repository remains active with occasional commits.

License in practice: MIT license is permissive, allowing commercial and private use with minimal restrictions—only requiring license and copyright notice preservation.

Quickstart:

pip install llist

from llist import dllist, sllist

dl = dllist([1, 2, 3])
sl = sllist([1, 2, 3])

Requires a C compiler and CPython development headers to build the extension during installation.

Verify before relying:

- Whether the package works reliably on modern Python versions (3.10+) given the long dormancy since 2021.
- Performance comparison with collections.deque on current Python versions to validate the claimed speed advantage.
- Compatibility with recent CPython releases and whether any breaking changes have occurred.

## Package facts

- License: MIT (permissive)
- Python support: unspecified
- Install friction: high
- Maintenance: dormant
- Downloads: 136.0K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

linked list data structure, fast insertion deletion middle, doubly linked list, singly linked list, dllist sllist, efficient sequence operations, cpython extension module, data-structure, c-extension, performance-oriented

[View on SkillFed](https://skillfed.io/packages/llist) · [View on PyPI](https://pypi.org/project/llist/)