altgraph

library0.17.5pypypi✓ verified 10d ago

altgraph is a foundational Python library for creating and manipulating directed and undirected graphs (networks). It provides a robust set of tools for graph data structures and basic algorithms, often used as a dependency in projects like PyInstaller. The current version is 0.17.5, with sporadic but active maintenance and releases typically a few times a year.

data

pip install altgraph

github ↗package ↗homepage ↗docs ↗

INSTALL

IMPORT

SIG · ALTGRAPH

altgraph

datapythonv0.17.5

Install

1.5s avg

Import

—

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 v0.17.5 · 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 0.000s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.5s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

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

Graph

✓ from altgraph.Graph import Graph

Dot

✓ from altgraph.Dot import Dot

Used for Graphviz integration.

Demonstrates creating a simple directed graph, adding nodes and edges, and basic traversal operations.

from altgraph.Graph import Graph # Create a new graph g = Graph() # Add nodes g.add_node("Start") g.add_node("Mid") g.add_node("End") # Add edges g.add_edge("Start", "Mid") g.add_edge("Mid", "End") g.add_edge("Start", "End", label="direct") print(f"Nodes: {list(g.nodes())}") print(f"Edges: {list(g.edges())}") print(f"Successors of 'Start': {list(g.forw_nodes("Start"))}") print(f"Predecessors of 'End': {list(g.back_nodes("End"))}") # Example of iterating over nodes and edges for node in g.nodes(): print(f"Node: {node}") for head, tail, data in g.edges(): print(f"Edge: {head} -> {tail} (data: {data})")

Debug

Known issues

breakingVersion 0.17.0 and newer dropped support for Python 2.x and older Python 3.x versions (3.3, 3.4, 3.5). If you are using these older Python interpreters, you must use altgraph < 0.17.

fix

Upgrade to a supported Python version (3.6+) or pin altgraph to a version less than 0.17 (e.g., `altgraph==0.16.1`).

affects: >=0.17.0

gotchaWhen using `altgraph.Dot` for visualizing graphs, the Graphviz system package must be installed and accessible in your system's PATH. This is an external dependency, not a Python package.

fix

Install Graphviz separately for your operating system (e.g., `sudo apt-get install graphviz` on Debian/Ubuntu, `brew install graphviz` on macOS, or download from graphviz.org).

affects: All

gotchaaltgraph provides fundamental graph structures and basic algorithms. For advanced graph analytics, highly optimized performance on massive graphs, or a richer set of algorithms (e.g., shortest path, centrality), users might need to integrate with more specialized libraries like NetworkX or igraph.

fix

Consider `NetworkX` or `igraph` for complex graph analysis, or use `altgraph` as a foundational layer and implement custom algorithms as needed.

affects: All

breakingThe provided test script `script.py` contains a `SyntaxError: f-string: unmatched '('` on line 18, preventing its execution. This error is due to an issue in the script's syntax, not directly a problem with the `altgraph` library or its compatibility.

fix

Correct the syntax error in `script.py` on line 18 by ensuring all parentheses within the f-string are properly matched.

affects: All

breakingThe `Graph.add_edge()` method in `altgraph` does not accept a `label` keyword argument directly. Edge attributes, such as a 'label', must be passed via the `attr` dictionary argument (e.g., `attr={'label': 'direct'}`).

fix

Modify the call to `add_edge()` to pass edge attributes through the `attr` dictionary argument, like so: `g.add_edge('Start', 'End', attr={'label': 'direct'})`.

affects: All

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'altgraph'

The 'altgraph' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install altgraph'.

ImportError: cannot import name 'Graph' from 'altgraph'

The 'Graph' class is located in the 'altgraph.Graph' submodule, not directly in 'altgraph'.

fix

Import the class correctly: 'from altgraph.Graph import Graph'.

AttributeError: module 'altgraph' has no attribute 'Graph'

Attempting to access 'Graph' directly from 'altgraph' instead of its submodule.

fix

Use the correct import statement: 'from altgraph.Graph import Graph'.

TypeError: 'Graph' object is not callable

Trying to call a 'Graph' object as if it were a function.

fix

Ensure that 'Graph' is instantiated correctly: 'g = Graph()' instead of 'g = Graph' followed by 'g()'.

ValueError: Node 'X' already exists in the graph

Attempting to add a node that already exists in the graph.

fix

Check if the node exists before adding it, or handle the exception appropriately.

Upgrade

Version history

0.17.5latest on PyPI · released Nov 21, 2025

Audit

Dependencies

No dependency data recorded yet.

Agent activity

39 hits · last 30 days

node

Resources

githubhttps://github.com/ronaldoussoren/altgraph ↗

packagehttps://pypi.org/project/altgraph/ ↗

homepagehttps://altgraph.readthedocs.io ↗

docshttps://altgraph.readthedocs.io/en/latest/ ↗