Warning message in set_channel_types causes KeyError #2878
Description
Hi there. I have some data which I read in using this code:
raw = mne.io.Raw(f, preload=True)
If I then take a look at an individual channel in the info structure, it looks like this:
raw.info['chs'][ch_names.index('EEG 1')]
{'cal': 1.0,
'ch_name': u'EEG 1',
'coil_type': 0,
'coord_frame': 0,
'kind': 0,
'loc': array([ 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.]),
'logno': 1,
'range': 1.0,
'scanno': 1,
'unit': 0,
'unit_mul': 0}
Now I want to set the channel type to 'misc' for all channels using set_channel_types(), but it blows up:
ch_types = dict([(chnm, 'misc') for chnm in raw.ch_names])
raw.set_channel_types(ch_types)
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-14-fc7277662040> in <module>()
1 ch_types = dict([(chnm, 'misc') for chnm in raw.ch_names])
----> 2 raw.set_channel_types(ch_types)
/home/despoB/arjun/anaconda2/lib/python2.7/site-packages/mne/channels/channels.pyc in set_channel_types(self, mapping)
289 warnings.warn("The unit for Channel %s has changed "
290 "from %s to %s." % (ch_name,
--> 291 _unit2human[unit_old],
292 _unit2human[unit_new]))
293 self.info['chs'][c_ind]['unit'] = _human2unit[ch_type]
KeyError: 0
> /home/despoB/arjun/anaconda2/lib/python2.7/site-packages/mne/channels/channels.py(291)set_channel_types()
290 "from %s to %s." % (ch_name,
--> 291 _unit2human[unit_old],
292 _unit2human[unit_new]))
It blows up because unit_old was 0, and _unit2human doesn't have a key 0. This warning message should check unit_old exists in _unit2human or something.