Calculate the factorial of 8. To do this, generate an array with values 1 to 8 and call the prod() function on it:

b = np.arange(1, 9)
print("b =", b)
print("Factorial", b.prod())

Check the result with your pocket calculator:

b = [1 2 3 4 5 6 7 8]
Factorial 40320

This is nice, but what if we want to know all the factorials from 1 to 8?

No problem! Call the cumprod() method, which computes the cumulative product of an array:

print("Factorials", b.cumprod())

It's pocket calculator time again:

Factorials [    1     2     6    24   120   720  5040 40320]