Why is 2 * x * x faster than 2 * ( x * x ) in Python 3.x, for integers?

Question

The following Python 3.x integer multiplication takes on average between 1.66s and 1.77s:

import time
start_time = time.time()
num = 0
for x in range(0, 10000000         


        

Answer 1

If your benchmark is right (didn't check), it may come from the fact that Python integers may be two different things : native integers when they are small (with a quick computation), and big integers when they increase in size (slower computation). The first syntax keeps the size smaller after the first operation while the second syntax may lead to two operations involving big integers.