python中怎么得出斐波那契数列第n项及前n项和？

用for循环求斐波那契数列中第n个数的值：

n = int(input('请输入要一个整数：'))

n_2 = 0

n_1 = 1

current = 1

for x in range(2, n+1):

current = n_2 + n_1

n_2 = n_1

n_1 = current

print('第%d个数是%d'%(n, current))

求斐波那契数列前N项之和:

n = int(input("Input N: "))

a = 0

b = 1

sum = 0

for i in range(n):

sum += a

a, b = b, a + b

print("The sum of", n, "FIB is", sum,"!")