# Bug in Epochs.save() and Raw.save() **URL:** \ **Category:** Support & Discussions\ **Created:** [May 18, 2023, 10:22am UTC](https://mne.discourse.group/t/bug-in-epochs-save-and-raw-save/6918 "2023-05-18T10:22:38Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![AR6789](https://avatars.discourse-cdn.com/v4/letter/a/58f4c7/32.png) [@AR6789](https://mne.discourse.group/u/AR6789)\ **Post date:** [May 18, 2023, 10:22am UTC](https://mne.discourse.group/t/bug-in-epochs-save-and-raw-save/6918/1 "2023-05-18T10:22:38Z")
Dear mne Forum. -Using mne 1.4.0 My EEG data is of the persyst type, mne.io.read\_raw\_persyst(). I created fixed length epochs of 30 seconds and want to save them in my files. I got an error when saving, the same error occures when i tried to save the raw\_preprocessed file. `epochs.save('epochs_epo.fif', overwrite = True)` The error: ````python AssertionError Traceback (most recent call last) Cell In[60], line 1 ----> 1 epochs.save('epochs_epo.fif', overwrite = True) File :12, in save(self, fname, split_size, fmt, overwrite, split_naming, verbose) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:2153, in BaseEpochs.save(self, fname, split_size, fmt, overwrite, split_naming, verbose) 2151 # avoid missing event_ids in splits 2152 this_epochs.event_id = self.event_id -> 2153 _save_split( 2154 this_epochs, fname, part_idx, n_parts, fmt, split_naming, overwrite 2155 ) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:150, in _save_split(epochs, fname, part_idx, n_parts, fmt, split_naming, overwrite) 147 next_idx = None 149 with start_and_end_file(fname) as fid: --> 150 _save_part(fid, epochs, fmt, n_parts, next_fname, next_idx) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:163, in _save_part(fid, epochs, fmt, n_parts, next_fname, next_idx) 160 write_id(fid, FIFF.FIFF_PARENT_BLOCK_ID, info["meas_id"]) 162 # Write measurement info --> 163 write_meas_info(fid, info) 165 # One or more evoked data sets 166 start_block(fid, FIFF.FIFFB_PROCESSED_DATA) ... --> 121 assert len(data) == 3 122 data_size = 4 123 jd = np.sum(_cal_to_julian(*data)) AssertionError: Output is truncated. View as a scrollable element or open in a text editor. Adjust cell output settings...``` The error occurs with the assert len(data) == 3 Is this a bug in the `Epochs.save()` format? The same error occurs when i tried saving the raw via `raw.save()` Thanks in advance. Kind regards, Aron Segers ```` ---
**Author:** ![wmvanvliet](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/wmvanvliet/32/100_2.png) [@wmvanvliet](https://mne.discourse.group/u/wmvanvliet)\ **Post date:** [May 19, 2023, 8:38am UTC](https://mne.discourse.group/t/bug-in-epochs-save-and-raw-save/6918/2 "2023-05-19T08:38:11Z")
Translating the error: “I expected `epochs.get_data()` to be an array with 3 dimensions, but it isn’t, and now I don’t know what to do”. Could you check whether `epochs.get_data().shape` makes sense? It could be a bug somewhere else. ---
**Author:** ![AR6789](https://avatars.discourse-cdn.com/v4/letter/a/58f4c7/32.png) [@AR6789](https://mne.discourse.group/u/AR6789)\ **Post date:** [May 19, 2023, 10:18am UTC](https://mne.discourse.group/t/bug-in-epochs-save-and-raw-save/6918/3 "2023-05-19T10:18:22Z")
If i run the `epochs.get_data().shape` I get a 3-dimensional array. Maybe there is a bug somewhere else than? I pasted my code and the error i recieved again ```python epochs = mne.make_fixed_length_epochs(raw_eeg_cropped, duration=30, preload= True) print(f'The shape of the epochs array : {epochs.get_data().shape}') epochs.save('epochs-epo.fif') ``` ```python Not setting metadata 180 matching events found No baseline correction applied Created an SSP operator (subspace dimension = 1) 1 projection items activated Using data from preloaded Raw for 180 events and 7680 original time points ... 0 bad epochs dropped The shape of the epochs array : (180, 37, 7680) Overwriting existing file. --------------------------------------------------------------------------- AssertionError Traceback (most recent call last) Cell In[25], line 3 1 epochs = mne.make_fixed_length_epochs(raw_eeg_cropped, duration=30, preload= True) 2 print(f'The shape of the epochs array : {epochs.get_data().shape}') ----> 3 epochs.save('epochs-epo.fif', overwrite = True) File :12, in save(self, fname, split_size, fmt, overwrite, split_naming, verbose) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:2153, in BaseEpochs.save(self, fname, split_size, fmt, overwrite, split_naming, verbose) 2151 # avoid missing event_ids in splits 2152 this_epochs.event_id = self.event_id -> 2153 _save_split( 2154 this_epochs, fname, part_idx, n_parts, fmt, split_naming, overwrite 2155 ) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:150, in _save_split(epochs, fname, part_idx, n_parts, fmt, split_naming, overwrite) 147 next_idx = None 149 with start_and_end_file(fname) as fid: --> 150 _save_part(fid, epochs, fmt, n_parts, next_fname, next_idx) File c:\Users\arons\anaconda_New3\envs\mne\lib\site-packages\mne\epochs.py:163, in _save_part(fid, epochs, fmt, n_parts, next_fname, next_idx) 160 write_id(fid, FIFF.FIFF_PARENT_BLOCK_ID, info["meas_id"]) 162 # Write measurement info --> 163 write_meas_info(fid, info) ... --> 121 assert len(data) == 3 122 data_size = 4 123 jd = np.sum(_cal_to_julian(*data)) AssertionError: ```