在python中实现求输出1-3+5-7+9-......101的和

i=0
sum=0
a=0
while i<102:
 if i>=1 and i%4==1:
  sum+=i
 elif i%2!=0 and i!=1:
  a=a+i
 i+=1
print(sum-a)

a=1
b=-3
sum1=0
sum2=0
while a<=101and b>=-99:
 sum1+=a
 sum2+=b
 a+=+4
 b+=-4
print(sum1+sum2+101)

L = [1, 3, 5, 7, 9, 50]
 
 
def func(n):
 if n == 1:
  return 1
 else:
  return n * func(n-1)
 
total = 0
 
for i in L:
 total = total + func(i)
print(total)

> def func(n):
...  return 1 if n == 1 else n * func(n-1)
> sum([func(i) for i in [1, 3, 5, 7, 9, 50]])
30414093201713378043612608166064768844377641568960512000000368047L

> from functools import reduce
> sum([reduce(lambda x,y:x*y, range(1, i+1)) for i in list(range(1, 10, 2)) + [50]])
30414093201713378043612608166064768844377641568960512000000368047L

> from scipy.special import factorial
> sum(factorial([1, 3, 5, 7, 9, 50], exact=True))
30414093201713378043612608166064768844377641568960512000000368047L