字符串反转? def reverse(s): if s "": return s else: print(s[1:]) return reverse(s[1:]) s[0] def main(): num "1234" print("num"num) num reverse(num) print("reverse"num) print("num[:-1]"num[:-1]) print(&…
http://en.wikipedia.org/wiki/Simpsons_paradox
http://zh.wikipedia.org/wiki/辛普森悖论
http://baike.baidu.com/view/965928.htm Simpsons paradox From Wikipedia, the free encyclopedia Simpsons paradox for continuous data: a positive trend appears for two …