Method add_vertex

graphs/graph_adjacency_list.py:60–77

Adds a vertex to the graph. If the given vertex already exists, a ValueError will be thrown. >>> g = GraphAdjacencyList(vertices=[], edges=[], directed=False) >>> g.add_vertex("A") >>> g.adj_list {'A': []} >>> g.add_vertex("A") Traceb

(self, vertex: T)

            self.add_edge(edge[0], edge[1])

    def add_vertex(self, vertex: T) -> None:
        """
        Adds a vertex to the graph. If the given vertex already exists,
        a ValueError will be thrown.

        >>> g = GraphAdjacencyList(vertices=[], edges=[], directed=False)
        >>> g.add_vertex("A")
        >>> g.adj_list
        {'A': []}
        >>> g.add_vertex("A")
        Traceback (most recent call last):
        ...
        ValueError: Incorrect input: A is already in the graph.
        """
        if self.contains_vertex(vertex):
            msg = f"Incorrect input: {vertex} is already in the graph."
            raise ValueError(msg)
        self.adj_list[vertex] = []

    def add_edge(self, source_vertex: T, destination_vertex: T) -> None:
        """