Help with simplifying a code + np.savetxt()

[scidam]

You are trying to add a string to an array of strings. The following is an example that reproduces the error:

>>> import numpy as np
>>> x=np.array(['sdf', 'sdf'])
>>> x + 'fsd'

Error:
numpy.core._exceptions.UFuncTypeError: ufunc 'add' did not contain a loop with signature matching types (dtype('<U3'), dtype('<U3')) -> dtype('<U3')