Add ScenarioInfo.substitute_codes()

message_ix_models/util/scenarioinfo.py

@@ -26,8 +26,8 @@ class ScenarioInfo:
     """Information about a :class:`.Scenario` object.
 
     Code that prepares data for a target Scenario can accept a ScenarioInfo instance.
-    This avoids the need to create or load an actual Scenario, which can be slow under
-    some conditions.
+    This avoids the need to create or load an actual Scenario or its data, which can be
+    a performance-limiting step.
 
     ScenarioInfo objects can also be used (for instance, by :func:`.apply_spec`) to
     describe the contents of a Scenario *before* it is created.
@@ -293,6 +293,28 @@ def io_units(
             )
         return c / t
 
+    def substitute_codes(self) -> None:
+        """Update the members of :attr:`set` using :func:`.get_codelist`.
+
+        Members of the following set(s) that are :class:`str` are replaced with codes
+        loaded from the corresponding code list(s), including all annotations:
+
+        - ``commodity``
+
+        .. todo:: Extend for other sets and cases where there are multiple code lists
+           (for instance ``year``, ``region``).
+        """
+        from message_ix_models.model.structure import get_codelist
+
+        for cl_id in ("commodity",):
+            cl = get_codelist(cl_id)
+            for i, value in enumerate(self.set[cl_id]):
+                if isinstance(value, str):
+                    try:
+                        self.set[cl_id][i] = cl[value]
+                    except KeyError:
+                        pass
+
     def year_from_codes(self, codes: List[sdmx_model.Code]):
         """Update using a list of `codes`.