Converting a Python list into a MATLAB cellstr through Python MATLAB engine

Hello there,

I have a list of paths to files (so basically strings) in Python, for example:

#python code  
lst = ['fls/01_1.nii', 'fls/02_1.nii', 'fls/03_1.nii', 'fls/04_1.nii']

What I'm trying to achieve is to move the list into MATLAB - I need to convert it into a 4x1 cell (the outcome in MATLAB would look like that):

    4×1 cell array

        {'fls/01_1.nii'}
        {'fls/02_1.nii'}
        {'fls/03_1.nii'}
        {'fls/04_1.nii'}

What I've done so far in Python:

import matlab.engine, matlab
eng = matlab.engine.start_matlab()
#first option
eng.workspace['matlab_list'] = lst
#second option
eng.workspace['matlab_list'] = eng.cellstr(lst)
#third option
eng.workspace['matlab_list'] = eng.reshape(eng.cellstr(lst), 4, 1)
#fourth option
eng.workspace['matlab_list'] = lst
eng.workspace['matlab_list'] = eng.eval("cellstr(lst)")

The code above should pretty much do the trick - my MATLAB engine even tells me that I'm dealing with a cell:

In[73]: eng.eval('class(matlab_list)')
Out[73]: 'cell'

Sadly, whenever I try to use that variable in a function from SPM (MATLAB based software package used in analysis of brain imaging data sequences), I'm getting an error:

Item 'Time 1 Volumes', field 'val': Value must be either empty, a cellstr or a cfg_dep object.

Here's what shows up in MATLAB_R2018a if I save the variable into a .mat file and try loading it there:

matlab_list =

    4×12 char array

      'fls/01_1.nii'
      'fls/02_1.nii'
      'fls/03_1.nii'
      'fls/04_1.nii' 

>> cellstr(matlab_list)

ans =

    4×1 cell array

      {'fls/01_1.nii'}
      {'fls/02_1.nii'}
      {'fls/03_1.nii'}
      {'fls/04_1.nii'}

Using the cellstr() function does the trick in MATLAB, but now I'm pretty keen on finding a way to change the char array into a cell array using Python MATLAB engine - so far no luck and I'm out of ideas at the moment.

I would be very grateful for any help or suggestions on fixing this particular issue.

Best Regards,

MG

Answer 1

[Jinjie Qi]

This is NOT work!