python - 在 Python 中，为什么“sum([int(digit) for digit in str(n))”比“sum(int(digit) for digit in str(n))”快？

Question

我想知道它：

> %timeit sum([int(digit) for digit in str(n)])
100000 loops, best of 3: 1.52 us per loop

> %timeit sum(int(digit) for digit in str(n))
100000 loops, best of 3: 2.04 us per loop