dgl.DGLGraph.num_edges

DGLGraph.num_edges(etype=None)

Return the number of edges in the graph.

Parameters:

etype (str or (str, str, str), optional) –

The type name of the edges. The allowed type name formats are:

• (str, str, str) for source node type, edge type and destination node type.

• or one str edge type name if the name can uniquely identify a triplet format in the graph.

If not provided, return the total number of edges regardless of the types in the graph.

Returns:

The number of edges.

Return type:

int

Examples

The following example uses PyTorch backend.

>>> import dgl
>>> import torch

Create a graph with three canonical edge types.

>>> g = dgl.heterograph({
...     ('user', 'follows', 'user'): (torch.tensor([0, 1]), torch.tensor([1, 2])),
...     ('user', 'follows', 'game'): (torch.tensor([0, 1, 2]), torch.tensor([1, 2, 3])),
...     ('user', 'plays', 'game'): (torch.tensor([1, 3]), torch.tensor([2, 3]))
... })

Query for the number of edges.

>>> g.num_edges('plays')
2
>>> g.num_edges()
7

Use a canonical edge type instead when there is ambiguity for an edge type.

>>> g.num_edges(('user', 'follows', 'user'))
2
>>> g.num_edges(('user', 'follows', 'game'))
3