python小问题记录：

numpy.chararray.flatten

chararray.flatten(order='C')
Return a copy of the array collapsed into one dimension.

Parameters :	order : {‘C’, ‘F’, ‘A’}, optional Whether to flatten in C (row-major), Fortran (column-major) order, or preserve the C/Fortran ordering from a. The default is ‘C’.
Returns :	y : ndarray A copy of the input array, flattened to one dimension.

See also

ravelReturn a flattened array.flatA 1-D flat iterator over the array.
Examples

>>> a = np.array([[1,2], [3,4]])
>>> a.flatten()
array([1, 2, 3, 4])
>>> a.flatten('F')
array([1, 3, 2, 4])