# Python graph

## Introduction

A graph in mathematics and computer science consists of “nodes” which may or may not be connected with one another. Connections between nodes are called edges. A graph can be directed (arrows) or undirected. The edges could represent distance or weight.

default graph (left), directed graph (right)

Python does not have a graph data type. To use graphs we can either use a module or implement it ourselves:

- implement graphs ourselves
- networkx module

**Related course**

Complete Python Bootcamp: Go from zero to hero in Python

## Graph in Python

A directed graph can be defined as:

#!/usr/bin/env python |

## Graphs using networkx

The networkx software module has support for creating, manipulating graphs.

#!/usr/bin/env python |

Result:

Nodes: [‘A’, ‘C’, ‘B’]

Edges: [(‘A’, ‘C’), (‘A’, ‘B’), (‘C’, ‘B’)]

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## 3 thoughts on “Python graph”

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- December 28, 2015

import networkx as nx

dosen’t work syntaxerror

- December 28, 2015

Install the networkx module using: pip install networkx

- August 29, 2016

You will need to install virtualenv on OSX otherwise you will have trouble installing networkx module.