I would write it like this, to avoid constructing the immediate list: sum_of_squares = sum(x*x for x in arr) This makes use of https://www.python.org/dev/

I would write it like this, to avoid constructing the immediate list: sum_of_squares = sum(x*x for x in arr) This makes use of https://www.python.org/dev/peps/pep-0289/ https://www.python.org/dev/peps/pep-0289/