data=data.frame("student"=c(1,1,1,1,2,2,2,3,3,3,3,4,4,4,4),
"year"=c(2014,2015,2016,2017,2014,2015,2016,2014,2015,2016,2017,2014,2015,2016,2017),
"grade"=c(9,10,11,12,9,10,11,9,10,11,12,9,10,11,12),
"score"=c(0,0,0,0,0,0,2,0,1,1,2,0,0,1,1)) 对于每个学生,我要报告第一个分数>0和出现这种