How to detect a cycle in a directed graph with Python?

Question

I have some input like: [(\'A\', \'B\'),(\'C\', \'D\'),(\'D\', \'C\'),(\'C\', \'D\')]. I want to look for if the existence of a cycle in a directed graph repres

Answer 1

Using the networkx library, we can use the simple_cycles function to find all simple cycles of a directed Graph.

Example Code:

import networkx as nx

edges = [('A', 'B'),('C', 'D'),('D', 'C'),('C', 'D')]

G = nx.DiGraph(edges)

for cycle in nx.simple_cycles(G):
    print(cycle)

G = nx.DiGraph()

G.add_edge('A', 'B')
G.add_edge('B', 'C')
G.add_edge('C', 'A')

for cycle in nx.simple_cycles(G):
    print(cycle)

Output:

['D', 'C']
['B', 'C', 'A']