altgraph

0.17.5 · active · verified Thu Apr 09

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.

Warnings

breaking Version 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`).
gotcha When 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).
gotcha altgraph 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.

Install

pip install altgraph Install latest version

Imports

Graph
```
from altgraph.Graph import Graph
```
Dot
```
from altgraph.Dot import Dot
```
Used for Graphviz integration.

Quickstart

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})")

view raw JSON →