Why is this code not an infinite loop?

[buran]

this is for loop, not while loop. There is no condition to check and decide to continue or not the loop, i.e. the value of i is irrelevant if there will be next iteration or not. you are free to use/assign new value to i in the loop body, e.g.

for i in range(3):
    i *= 2
    print(i)