def discard_vertex(self, vid: base.VertexID) -> bool:
"""
Remove the vertex associated with this ID from the graph. If such a vertex does not exist, do nothing. Any
incident edges to the vertex are also removed. Return a Boolean indicating whether the vertex was present to
be removed.
"""
if vid not in self._forward:
return False
# Remove labels and data
if vid in self._vertex_labels:
del self._vertex_labels[vid]
if vid in self._vertex_data:
del self._vertex_data[vid]
# Remove all incident edges.
for sink in self._forward[vid]:
self.discard_edge(base.DirectedEdgeID(vid, sink), ignore=vid)
for source in self._backward[vid]:
self.discard_edge(base.DirectedEdgeID(source, vid), ignore=vid)
for other in self._dual[vid]:
self.discard_edge(base.UndirectedEdgeID(vid, other), ignore=vid)
# Remove the vertex itself
del self._forward[vid]
del self._backward[vid]
del self._dual[vid]
return True
def iter_outbound(self,
source: base.VertexID) -> Iterator[base.DirectedEdgeID]:
"""Return an iterator over the IDs of every outbound directed edge from this vertex."""
try:
for key in self._read_vertex(source)[SINKS_INDEX]:
yield base.DirectedEdgeID(source, key)
except KeyError:
pass
def iter_inbound(self,
sink: base.VertexID) -> Iterator[base.DirectedEdgeID]:
"""Return an iterator over the IDs of every inbound directed edge to this vertex."""
try:
for key in self._read_vertex(sink)[SOURCES_INDEX]:
yield base.DirectedEdgeID(key, sink)
except KeyError:
pass
def _decode_key(encoded_key: bytes, prefix: bytes) -> Any:
"""Decode a key from a byte string. This is the inverse of the _encode_key() method."""
assert encoded_key.startswith(prefix)
result = ast.literal_eval(encoded_key[len(prefix):].decode())
if prefix == EID_PREFIX:
(vid1, vid2), directed = result
if directed:
result = base.DirectedEdgeID(vid1, vid2)
else:
result = base.UndirectedEdgeID(vid1, vid2)
return result
def discard_vertex(self, vid: base.VertexID) -> bool:
"""
Remove the vertex associated with this ID from the graph. If such a vertex does not exist, do nothing. Any
incident edges to the vertex are also removed. Return a Boolean indicating whether the vertex was present to
be removed.
"""
try:
_, _, sources, sinks, undirected = self._read_vertex(vid)
except KeyError:
return False
for source in sources:
self.discard_edge(base.DirectedEdgeID(source, vid), ignore=vid)
for sink in sinks:
self.discard_edge(base.DirectedEdgeID(vid, sink), ignore=vid)
for other in undirected:
self.discard_edge(base.UndirectedEdgeID(vid, other), ignore=vid)
self._del_vertex(vid)
self._v_count = self.count_vertices() - 1
self._v_count_dirty = True
return True
def iter_edges(self) -> Iterator[base.EdgeID]:
"""Return an iterator over the IDs of every edge in the graph."""
for source, sinks in self._forward.items():
for sink in sinks:
yield base.DirectedEdgeID(source, sink)
# We have to guarantee that each edge is only yielded once, which is a bit more complicated when edges
# are undirected. We do that by imposing an artificial order on the IDs (since IDs are not required to be
# ordered). I know repr is slow, but it's better than building a set to avoid duplicates.
for left, rights in self._dual.items():
if left in rights:
yield base.UndirectedEdgeID(left, left)
left_repr = repr(left)
for right in rights:
if left != right and left_repr < repr(right):
yield base.UndirectedEdgeID(left, right)
def iter_outbound(self,
source: base.VertexID) -> Iterator[base.DirectedEdgeID]:
"""Return an iterator over the IDs of every outbound directed edge from this vertex."""
for sink in self._backward.get(source, ()):
yield base.DirectedEdgeID(source, sink)
def iter_inbound(self,
sink: base.VertexID) -> Iterator[base.DirectedEdgeID]:
"""Return an iterator over the IDs of every inbound directed edge to this vertex."""
for source in self._backward.get(sink, ()):
yield base.DirectedEdgeID(source, sink)