python3-numpy: Appending to a file using numpy savetxt

Solution 1:

You should open file by binary mode.

#!/usr/bin/env python3
import numpy as np        
f=open('asd.dat','ab')
for iind in range(4):
    a=np.random.rand(10,10)
    np.savetxt(f,a)
f.close()

reference: python - How to write a numpy array to a csv file? - Stack Overflow How to write a numpy array to a csv file?