在论坛上没搜到，所以拿来共享。希望能帮到需要的童鞋~象征性的收一个币，感谢支持

A Tutorial on the SWEEP Operator
Author(s): James H. Goodnight
Source: The American Statistician, Vol. 33, No. 3 (Aug., 1979), pp. 149-158
Published by: American Statistical Association