Add spec find_sensor, find_actuator functions.

PiperOrigin-RevId: 703054696
Change-Id: Ie384f1a31de3ecd9b22b7f4be43234d452e7bb88

python/mujoco/specs.cc

@@ -350,6 +350,20 @@ PYBIND11_MODULE(_specs, m) {
         return mjs_asSite(mjs_findElement(self.ptr, mjOBJ_SITE, name.c_str()));
       },
       py::return_value_policy::reference_internal);
+  mjSpec.def(
+      "find_actuator",
+      [](MjSpec& self, std::string& name) -> raw::MjsActuator* {
+        return mjs_asActuator(
+            mjs_findElement(self.ptr, mjOBJ_ACTUATOR, name.c_str()));
+      },
+      py::return_value_policy::reference_internal);
+  mjSpec.def(
+      "find_sensor",
+      [](MjSpec& self, std::string& name) -> raw::MjsSensor* {
+        return mjs_asSensor(
+            mjs_findElement(self.ptr, mjOBJ_SENSOR, name.c_str()));
+      },
+      py::return_value_policy::reference_internal);
   mjSpec.def(
       "find_default",
       [](MjSpec& self, std::string& classname) -> const raw::MjsDefault* {

python/mujoco/specs_test.py

@@ -584,13 +584,29 @@ class SpecsTest(absltest.TestCase):
     sensor1 = spec.add_sensor()
     sensor2 = spec.add_sensor()
     sensor3 = spec.add_sensor()
+    actuator1 = spec.add_actuator()
+    actuator2 = spec.add_actuator()
+    actuator3 = spec.add_actuator()
     sensor1.name = 'sensor1'
     sensor2.name = 'sensor2'
     sensor3.name = 'sensor3'
+    actuator1.name = 'actuator1'
+    actuator2.name = 'actuator2'
+    actuator3.name = 'actuator3'
     self.assertLen(spec.sensors, 3)
+    self.assertLen(spec.actuators, 3)
     self.assertEqual(spec.sensors[0].name, 'sensor1')
     self.assertEqual(spec.sensors[1].name, 'sensor2')
     self.assertEqual(spec.sensors[2].name, 'sensor3')
+    self.assertEqual(spec.actuators[0].name, 'actuator1')
+    self.assertEqual(spec.actuators[1].name, 'actuator2')
+    self.assertEqual(spec.actuators[2].name, 'actuator3')
+    self.assertEqual(spec.find_sensor('sensor1'), sensor1)
+    self.assertEqual(spec.find_sensor('sensor2'), sensor2)
+    self.assertEqual(spec.find_sensor('sensor3'), sensor3)
+    self.assertEqual(spec.find_actuator('actuator1'), actuator1)
+    self.assertEqual(spec.find_actuator('actuator2'), actuator2)
+    self.assertEqual(spec.find_actuator('actuator3'), actuator3)
 
   def test_body_list(self):
     main_xml = """