python中如何求阶乘

import functools

result = (lambda k: functools.reduce(int.__mul__, range(1, k + 1), 1))(5)

print(result)

x = 1

y = int(input("请输入要计算的数:"))

for i in range(1, y + 1):

  x = x * i

print(x)

def func(n):

  if n == 0 or n == 1:

    return 1

  else:

    return (n * func(n - 1))

a = func(5)

print(a)