Warning

This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.

networkx.MultiDiGraph.has_edge

MultiDiGraph.has_edge(u, v, key=None)

Return True if the graph has an edge between nodes u and v.

This is the same as v in G[u] or key in G[u][v] without KeyError exceptions.

Parameters:

• u, v (nodes) – Nodes can be, for example, strings or numbers.
• key (hashable identifier, optional (default=None)) – If specified return True only if the edge with key is found.

Returns:

edge_ind – True if edge is in the graph, False otherwise.

Return type:

bool

Examples

Can be called either using two nodes u, v, an edge tuple (u, v), or an edge tuple (u, v, key).

>>> G = nx.MultiGraph()   # or MultiDiGraph
>>> nx.add_path(G, [0, 1, 2, 3])
>>> G.has_edge(0, 1)  # using two nodes
True
>>> e = (0, 1)
>>> G.has_edge(*e)  #  e is a 2-tuple (u, v)
True
>>> G.add_edge(0, 1, key='a')
'a'
>>> G.has_edge(0, 1, key='a')  # specify key
True
>>> e=(0, 1, 'a')
>>> G.has_edge(*e) # e is a 3-tuple (u, v, 'a')
True

The following syntax are equivalent:

>>> G.has_edge(0, 1)
True
>>> 1 in G[0]  # though this gives :exc:`KeyError` if 0 not in G
True