range()函数的用法:
http://www.cnblogs.com/buro79xxd/archive/2011/05/23/2054493.html
大神用python写的打印三角形
n = 5
for i in range(n, 0, -1):
for s in range(i, 0, -1):
print ((n-s)*' '+(2*s -1)*'*') if s in (1, i) else ('%s*%s*' % ((n-s)*' ', (2*s -3)*' '))
显示如下: