Graph.py

#   Created by Elshad Karimov 
#   Copyright © 2023 AppMillers. All rights reserved.

class Graph:
    def __init__(self):
        self.adjacency_list = {}
    
    def add_vertex(self, vertex):
        if vertex not in self.adjacency_list.keys():
            self.adjacency_list[vertex] = []
            return True
        return False
    
    def print_graph(self):
        for vertex in self.adjacency_list:
            print(vertex,":",self.adjacency_list[vertex])
    
    def add_edge(self, vertex1, vertex2):
        if vertex1 in self.adjacency_list.keys() and vertex2 in self.adjacency_list.keys():
            self.adjacency_list[vertex1].append(vertex2)
            self.adjacency_list[vertex2].append(vertex1)
            return True
        return False
    
    def remove_edge(self, vertex1, vertex2):
        if vertex1 in self.adjacency_list.keys() and vertex2 in self.adjacency_list.keys():
            try:
                self.adjacency_list[vertex1].remove(vertex2)
                self.adjacency_list[vertex2].remove(vertex1)
            except ValueError:
                pass
            return True
        return False
    
    def remove_vertex(self, vertex):
        if vertex in self.adjacency_list.keys():
            for other_vertex in self.adjacency_list[vertex]:
                self.adjacency_list[other_vertex].remove(vertex)
            del self.adjacency_list[vertex]
            return True
        return False





my_graph = Graph()
my_graph.add_vertex("A")
my_graph.add_vertex("B")
my_graph.add_vertex("C")
my_graph.add_vertex("D")
my_graph.add_edge("A", "B")
my_graph.add_edge("A", "C")
my_graph.add_edge("A", "D")
my_graph.add_edge("B", "C")
my_graph.add_edge("C", "D")
my_graph.print_graph()
my_graph.remove_vertex("A")
print("After remove..")
my_graph.print_graph()