def sum_func(arr):
? ? if len(arr) <= 0:
? ? ? ? return 0
? ? else:
? ? ? ? out = arr[0]
? ? ? ? for v in arr[1:]:
? ? ? ? ? ? out += v
? ? ? ? return out

a = [1, 2, 3, 4, 5]
print(sum_func(a))

from functools import reduce

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

def add(x, y): return x + y

print(reduce(add, a))

from functools import reduce
import time

def test_for(arr):
? ? if len(arr) <= 0:
? ? ? ? return 0
? ? out = arr[0]
? ? for i in arr[1:]:
? ? ? ? out += i
? ? return out


def test_reduce(arr):
? ? out = reduce(lambda x, y: x + y, arr)
? ? return out

a = [i for i in range(100000)]
t1 = time.perf_counter()
test_for(a)
t2 = time.perf_counter()
test_reduce(a)
t3 = time.perf_counter()
print('for循環(huán)耗時:', (t2 - t1))
print('reduce耗時:', (t3 - t2))