python中的reduce

from functools import reduce

num_1 = [1, 2, 3, 4, 5]

#加法
def reduce_test(array):
    res = 0
    for num in num_1:
        res += num
    return res

#乘法

def reduce_test(func, array, init=None):
    if init is None:
        res = array.pop(0)
    else:
        res = init
    for num in num_1:
        res *= func(res, num)
    return res

print(reduce_test(lambda x, y: x*y, num_1)

# reduce函数
 res = reduce(lambda x, y: x+y, num_1, 1)  
 print(res)