In [1]: import cantera as ct
...: gas = ct.Solution('gri30.yaml')
...: arr = ct.SolutionArray(gas, 10, extra={'new_column': range(10)})
In [2]: arr.new_column[0] = 10
The assignment does not work, i.e.
In [3]: arr.new_column
Out[3]: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
See above.