python圣斗士修炼（八）：小试牛刀

实现1-100的和

sum = 0
for i in xrange(1,101):
    sum +=i
print (sum)

5050

标题 ##实现1-500奇数的和

sum = 0
for i in xrange(1,501,2):
    sum +=i
print (sum)

62500

求1+ 2! + 3! + 4! + ……20！的和

b=1
sum=0
for i in xrange(1,21):
    b *=i
    sum +=b
print sum

2561327494111820313

对指定一个list进行排序

l= [2,32,43,453,54,6,576,5,7,6,8,78,7,89]
l.sort()
print l
#反排序
l.reverse()
print l

[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
[576, 453, 89, 78, 54, 43, 32, 8, 7, 7, 6, 6, 5, 2]