How can I store float probabilities to a file so exactly that they sum up to 1?

Question

I want to store a numpy array to a file. This array contains thousands of float probabilities which all sum up to 1. But when I store the array to a CSV file and load it back, I realise that the numbers have been approximated, and their sum is now some 0.9999 value. How can I fix it?

(Numpy's random choice method requires probabilities to sum up to 1)

Answer 1

Try using np.savetxt.

import numpy as np

arr = np.random.random(1000)
arr /= arr.sum()
np.savetxt('arr.csv', arr, delimiter=',')

arr = np.loadtxt('arr.csv')
print(arr.sum())
# >>> 1.0