review

mne/epochs.py

@@ -488,10 +488,7 @@ def __init__(
         if events is not None:  # RtEpochs can have events=None
             for key, val in self.event_id.items():
                 if val not in events[:, 2]:
-                    msg = "No matching events found for %s " "(event id %i)" % (
-                        key,
-                        val,
-                    )
+                    msg = f"No matching events found for {key} (event id {val})"
                     _on_missing(on_missing, msg)
 
             # ensure metadata matches original events size
@@ -3105,6 +3102,40 @@ def _ensure_list(x):
     return metadata, events, event_id
 
 
+def _events_from_annotations(raw, events, event_id, annotations, on_missing):
+    """Generate events and event_ids from annotations."""
+    events, event_id_tmp = events_from_annotations(raw)
+    if events.size == 0:
+        raise RuntimeError(
+            "No usable annotations found in the raw object. "
+            "Either `events` must be provided or the raw "
+            "object must have annotations to construct epochs"
+        )
+    if any(raw.annotations.duration > 0):
+        logger.info(
+            "Ignoring annotation durations and creating fixed-duration epochs "
+            "around annotation onsets."
+        )
+    if event_id is None:
+        event_id = event_id_tmp
+    # if event_id is the names of events, map to events integers
+    if isinstance(event_id, str):
+        event_id = [event_id]
+    if isinstance(event_id, (list, tuple, set)):
+        if not set(event_id).issubset(set(event_id_tmp)):
+            msg = (
+                "No matching annotations found for event_id(s) "
+                f"{set(event_id) - set(event_id_tmp)}"
+            )
+            _on_missing(on_missing, msg)
+        # remove extras if on_missing not error
+        event_id = set(event_id) & set(event_id_tmp)
+        event_id = {my_id: event_id_tmp[my_id] for my_id in event_id}
+        # remove any non-selected annotations
+        annotations.delete(~np.isin(raw.annotations.description, list(event_id)))
+    return events, event_id, annotations
+
+
 @fill_doc
 class Epochs(BaseEpochs):
     """Epochs extracted from a Raw instance.
@@ -3262,35 +3293,9 @@ def __init__(
 
         # get events from annotations if no events given
         if events is None:
-            events, event_id_tmp = events_from_annotations(raw)
-            if events.size == 0:
-                raise RuntimeError(
-                    "No usable annotations found in the raw object. "
-                    "Either `events` must be provided or the raw "
-                    "object must have annotations to construct epochs"
-                )
-            if any(raw.annotations.duration > 0):
-                logger.info(
-                    "Ignoring annotation durations and creating fixed-duration epochs "
-                    "around annotation onsets."
-                )
-            if event_id is None:
-                event_id = event_id_tmp
-            # if event_id is the names of events, map to events integers
-            if isinstance(event_id, str):
-                event_id = [event_id]
-            if isinstance(event_id, (list, tuple, set)):
-                if set(event_id).issubset(set(event_id_tmp)):
-                    event_id = {my_id: event_id_tmp[my_id] for my_id in event_id}
-                    # remove any non-selected annotations
-                    annotations.delete(
-                        ~np.isin(raw.annotations.description, list(event_id))
-                    )
-                else:
-                    raise RuntimeError(
-                        f"event_id(s) {set(event_id) - set(event_id_tmp)} "
-                        "not found in annotations"
-                    )
+            events, event_id, annotations = _events_from_annotations(
+                raw, events, event_id, annotations, on_missing
+            )
 
         # call BaseEpochs constructor
         super(Epochs, self).__init__(

mne/tests/test_epochs.py

@@ -1004,8 +1004,12 @@ def test_epochs_from_annotations():
             events, raw.info["sfreq"], first_samp=raw.first_samp
         )
     )
-    with pytest.raises(RuntimeError, match="not found in annotations"):
+    # test on_missing
+    with pytest.raises(ValueError, match="No matching annotations"):
         Epochs(raw, event_id="foo")
+    # test on_missing warn
+    with pytest.warns(match="No matching annotations"):
+        Epochs(raw, event_id=["1", "foo"], on_missing="warn")
 
 
 def test_epochs_hash():