Add in and out edge indices functions

rustworkx/rustworkx.pyi

@@ -1423,6 +1423,7 @@ class PyDiGraph(Generic[_S, _T]):
     def in_edges(self, node: int, /) -> WeightedEdgeList[_T]: ...
     def incident_edge_index_map(self, node: int, /, all_edges: bool = ...) -> EdgeIndexMap: ...
     def incident_edges(self, node: int, /, all_edges: bool = ...) -> EdgeIndices: ...
+    def in_edge_indices(self, node: int, /) -> EdgeIndices: ...
     def insert_node_on_in_edges(self, node: int, ref_node: int, /) -> None: ...
     def insert_node_on_in_edges_multiple(self, node: int, ref_nodes: Sequence[int], /) -> None: ...
     def insert_node_on_out_edges(self, node: int, ref_node: int, /) -> None: ...

src/digraph.rs

@@ -1842,6 +1842,29 @@ impl PyDiGraph {
         }
     }
 
+    /// Return the list of incoming edge indices to a provided node
+    ///
+    /// This method will return the incoming edges of the provided
+    /// ``node``.
+    ///
+    /// :param int node: The node index to get incoming edges from. If
+    ///     this node index is not present in the graph this method will
+    ///     return an empty list and not error.
+    ///
+    /// :returns: A list of the incoming edge indices to a node in the graph
+    /// :rtype: EdgeIndices
+    #[pyo3(text_signature = "(self, node, /)")]
+    pub fn in_edge_indices(&self, node: usize) -> EdgeIndices {
+        let node_index = NodeIndex::new(node);
+        EdgeIndices {
+            edges: self
+                .graph
+                .edges_directed(node_index, petgraph::Direction::Incoming)
+                .map(|e| e.id().index())
+                .collect(),
+        }
+    }
+
     /// Return the index map of edges incident to a provided node
     ///
     /// By default this method will only return the outgoing edges of

tests/digraph/test_edges.py

@@ -813,6 +813,23 @@ def test_incident_edges_all_edges(self):
         res = graph.incident_edges(node_d, all_edges=True)
         self.assertEqual([2, 1], res)
 
+    def test_in_edge_indices(self):
+        graph = rustworkx.PyDiGraph()
+        node_a = graph.add_node(0)
+        node_b = graph.add_node(1)
+        node_c = graph.add_node("c")
+        node_d = graph.add_node("d")
+        graph.add_edge(node_a, node_c, "edge a")
+        graph.add_edge(node_b, node_d, "edge b")
+        graph.add_edge(node_d, node_c, "edge c")
+        res = graph.in_edge_indices(node_c)
+        self.assertEqual([2, 0], res)
+
+    def test_in_edge_indices_invalid_node(self):
+        graph = rustworkx.PyDiGraph()
+        res = graph.in_edge_indices(0)
+        self.assertEqual([], res)
+
     def test_incident_edge_index_map(self):
         graph = rustworkx.PyDiGraph()
         node_a = graph.add_node(0)