# nan.py -*- coding: utf-8 -*- 

import numpy as np

height = np.array([45, 75, 60, 51, np.nan])
print(np.mean(height))
print(np.nanmean(height))

x = np.array([1, -1, 0, np.infty, -np.inf])
print(x/0)  # error message
print(x/np.Infinity)  # error message

print('e=', np.e, 'pi=', np.pi)