FIX: Make set_eeg_reference working with a string for a channel name (#13917)

Author: mistraube

doc/changes/dev/13917.bugfix.rst

@@ -0,0 +1 @@
+Fix bug with :func:`mne.set_eeg_reference` not working when passing a single channel name as string, by `Michael Straube`_.

mne/_fiff/reference.py

@@ -416,6 +416,10 @@ def set_eeg_reference(
         logger.info("Applying a custom dict-based reference.")
         return _apply_dict_reference(inst, ref_channels)
 
+    # We need 'ref_channels' to be a list, even for a single channel name.
+    if isinstance(ref_channels, str) and ref_channels not in ("average", "REST"):
+        ref_channels = [ref_channels]
+
     ch_type = _get_ch_type(inst, ch_type)
 
     if projection:  # average reference projector

mne/_fiff/tests/test_reference.py

@@ -257,6 +257,10 @@ def test_set_eeg_reference():
     with pytest.raises(ValueError, match='supported for ref_channels="averag'):
         set_eeg_reference(raw, ["EEG 001"], True, True)
 
+    # Test passing a single channel name as string
+    reref, ref_data = set_eeg_reference(raw, "EEG 001", copy=True)
+    _test_reference(raw, reref, ref_data, ["EEG 001"])
+
 
 @pytest.mark.parametrize(
     "ch_type, msg",

tutorials/intro/15_inplace.py

@@ -83,7 +83,7 @@
 # we specified ``copy=True``:
 
 # sphinx_gallery_thumbnail_number=2
-rereferenced_raw, ref_data = mne.set_eeg_reference(original_raw, ["EEG 003"], copy=True)
+rereferenced_raw, ref_data = mne.set_eeg_reference(original_raw, "EEG 003", copy=True)
 fig_orig = original_raw.plot()
 fig_reref = rereferenced_raw.plot()
 

tutorials/preprocessing/55_setting_eeg_reference.py

@@ -79,13 +79,13 @@
 # earlobe or mastoid channels, so this is just for demonstration purposes:
 
 # use a single channel reference (left earlobe)
-# raw.set_eeg_reference(ref_channels=['A1'])
+# raw.set_eeg_reference(ref_channels='A1')
 
 # use average of mastoid channels as reference
 # raw.set_eeg_reference(ref_channels=['M1', 'M2'])
 
 # use a bipolar reference (contralateral)
-# raw.set_bipolar_reference(anode='[F3'], cathode=['F4'])
+# raw.set_bipolar_reference(anode='F3', cathode='F4')
 
 # %%
 # If a scalp electrode was used as reference but was not saved alongside the
@@ -109,14 +109,14 @@
 # ``copy=False``.
 
 # add new reference channel (all zero)
-raw_new_ref = mne.add_reference_channels(raw, ref_channels=["EEG 999"])
+raw_new_ref = mne.add_reference_channels(raw, ref_channels="EEG 999")
 raw_new_ref.plot()
 
 # %%
 # .. KEEP THESE BLOCKS SEPARATE SO FIGURES ARE BIG ENOUGH TO READ
 
 # set reference to `EEG 050`
-raw_new_ref.set_eeg_reference(ref_channels=["EEG 050"])
+raw_new_ref.set_eeg_reference(ref_channels="EEG 050")
 raw_new_ref.plot()
 
 # %%
@@ -218,7 +218,7 @@
 # :footcite:`YaoEtAl2019` which creates a new virtual channel
 # named ``EEG 054-EEG 055``.
 
-raw_bip_ref = mne.set_bipolar_reference(raw, anode=["EEG 054"], cathode=["EEG 055"])
+raw_bip_ref = mne.set_bipolar_reference(raw, anode="EEG 054", cathode="EEG 055")
 raw_bip_ref.plot()
 
 # %%