save 2d array to file and load back

[scidam]

Default format string (fmt parameter) for the np.savetxt method coincide to floating point numbers, so, you need to change fmt to '%s' (strings):

import numpy as np
x = [['ABC', 123.45], ['DEF', 678.90]]
np.savetxt('text.txt', x, fmt='%s')

# default dtype for  np.loadtxt is also floating point, change it, to be able to load mixed data.
y = np.loadtxt('text.txt', dtype=np.object)