Add method: has_node

releasenotes/notes/add-has_node-method-9e6b91bf79e60f50.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Added a method :meth:`~rustworkx.PyGraph.has_node`
+    to the
+    :class:`~rustworkx.PyGraph` and :class:`~rustworkx.PyDiGraph`
+    classes to check if a node is in the graph.

rustworkx/rustworkx.pyi

@@ -1146,6 +1146,7 @@ class PyGraph(Generic[_S, _T]):
     def get_edge_data_by_index(self, edge_index: int, /) -> _T: ...
     def get_edge_endpoints_by_index(self, edge_index: int, /) -> tuple[int, int]: ...
     def get_node_data(self, node: int, /) -> _S: ...
+    def has_node(self, node: int, /) -> bool: ...
     def has_edge(self, node_a: int, node_b: int, /) -> bool: ...
     def has_parallel_edges(self) -> bool: ...
     def in_edges(self, node: int, /) -> WeightedEdgeList[_T]: ...
@@ -1303,6 +1304,7 @@ class PyDiGraph(Generic[_S, _T]):
     def get_node_data(self, node: int, /) -> _S: ...
     def get_edge_data_by_index(self, edge_index: int, /) -> _T: ...
     def get_edge_endpoints_by_index(self, edge_index: int, /) -> tuple[int, int]: ...
+    def has_node(self, node: int, /) -> bool: ...
     def has_edge(self, node_a: int, node_b: int, /) -> bool: ...
     def has_parallel_edges(self) -> bool: ...
     def in_degree(self, node: int, /) -> int: ...

src/digraph.rs

@@ -595,6 +595,18 @@ impl PyDiGraph {
         self.node_indices()
     }
 
+    /// Return True if there is a node in the graph.
+    ///
+    /// :param int node: The node index to check
+    ///
+    /// :returns: True if there is a node false if there is no node
+    /// :rtype: bool
+    #[pyo3(text_signature = "(self, node, /)")]
+    pub fn has_node(&self, node: usize) -> bool {
+        let index = NodeIndex::new(node);
+        self.graph.contains_node(index)
+    }
+
     /// Return True if there is an edge from node_a to node_b.
     ///
     /// :param int node_a: The source node index to check for an edge
@@ -3059,7 +3071,7 @@ impl PyDiGraph {
     /// required to return a boolean value stating whether the node's data payload fits some criteria.
     ///
     /// For example::
-    ///     
+    ///
     ///     from rustworkx import PyDiGraph
     ///
     ///     graph = PyDiGraph()
@@ -3107,8 +3119,8 @@ impl PyDiGraph {
     ///     def my_filter_function(edge):
     ///         if edge:
     ///             return edge == 'B'
-    ///         return False  
-    ///        
+    ///         return False
+    ///
     ///     indices = graph.filter_edges(my_filter_function)
     ///     assert indices == [1]
     ///

src/graph.rs

@@ -468,6 +468,18 @@ impl PyGraph {
         self.node_indices()
     }
 
+    /// Return True if there is a node.
+    ///
+    /// :param int node: The index for the node
+    ///
+    /// :returns: True if there is a node false if there is no node
+    /// :rtype: bool
+    #[pyo3(text_signature = "(self, node, /)")]
+    pub fn has_node(&self, node: usize) -> bool {
+        let index = NodeIndex::new(node);
+        self.graph.contains_node(index)
+    }
+
     /// Return True if there is an edge between ``node_a`` and ``node_b``.
     ///
     /// :param int node_a: The index for the first node
@@ -2039,7 +2051,7 @@ impl PyGraph {
     /// required to return a boolean value stating whether the node's data payload fits some criteria.
     ///
     /// For example::
-    ///     
+    ///
     ///     from rustworkx import PyGraph
     ///
     ///     graph = PyGraph()
@@ -2087,8 +2099,8 @@ impl PyGraph {
     ///     def my_filter_function(edge):
     ///         if edge:
     ///             return edge == 'B'
-    ///         return False  
-    ///        
+    ///         return False
+    ///
     ///     indices = graph.filter_edges(my_filter_function)
     ///     assert indices == [1]
     ///

tests/digraph/test_nodes.py

@@ -76,6 +76,12 @@ def test_remove_nodes_from_with_invalid_index(self):
         self.assertEqual(["a"], res)
         self.assertEqual([0], dag.node_indexes())
 
+    def test_has_node(self):
+        dag = rustworkx.PyDAG()
+        node_a = dag.add_node("a")
+        self.assertTrue(dag.has_node(node_a))
+        self.assertFalse(dag.has_node(node_a + 1))
+
     def test_remove_nodes_retain_edges_single_edge(self):
         dag = rustworkx.PyDAG()
         node_a = dag.add_node("a")

tests/graph/test_nodes.py

@@ -179,3 +179,9 @@ def test_remove_node_delitem_invalid_index(self):
         res = graph.nodes()
         self.assertEqual(["a", "b", "c"], res)
         self.assertEqual([0, 1, 2], graph.node_indexes())
+
+    def test_has_node(self):
+        graph = rustworkx.PyGraph()
+        node_a = graph.add_node("a")
+        self.assertTrue(graph.has_node(node_a))
+        self.assertFalse(graph.has_node(node_a + 1))