import numpy as np np.sqrt(25) np.sqrt(25) np.arange(3, 10) np.arange(10, 3, -1) np.arange(10, 3, -1, dtype='float') import time time.ctime() x = 16 x np.sqrt(x) x = np.arange(1, 7) x np.sqrt(x) x x = np.sqrt(x) choices = np.arange(1, 10000) np.random.choice(choices, 20, replace=False) # sample _without_ replacement np.random.choice(np.arange(1, 10000), 20, replace=False) 7. + 2. 3. * 4. 5. / 2. 3. - 8. -3. 5.**2. # same as 5^2 (or 5 to the power of 2) 8. + 4. / 2. (8. + 4.) / 2. 3.**2. np.sqrt(3.) # or 3.**0.5 8.**(1./3.) np.sin(np.pi) np.float64(1.) / 0. np.float64(0.) / 0. name = "python" name "name" name = python