perfomance of len(List) vs reading a variable

Question

A similar question has already been ask Cost of len() function here. However, this question looks at the cost of len it self. Suppose, I have a code that repea

Answer 1

Using l = len(li) is faster:

python -m timeit -s "li = [1, 2, 3]" "len(li)"
1000000 loops, best of 3: 0.239 usec per loop

python -m timeit -s "li = [1, 2, 3]; l = len(li)" "l"
10000000 loops, best of 3: 0.0949 usec per loop