想求平均值
我的数据库表里有4个学校的语文成绩和学校的考试人数,求平均值如下:
a=((SelectInfoVO)array1.get(0)).getYuwen_score()*((SelectInfoVO)array1.get(0)).getStu_num()+((SelectInfoVO)array1.get(1)).getYuwen_score()*((SelectInfoVO)array1.get(1)).getStu_num()+((SelectInfoVO)array1.get(2)).getYuwen_score()*((SelectInfoVO)array1.get(2)).getStu_num()+((SelectInfoVO)array1.get(3)).getYuwen_score()*((SelectInfoVO)array1.get(3)).getStu_num()
b=((SelectInfoVO)array1.get(0)).getStu_num+((SelectInfoVO)array1.get(1)).getStu_num
+((SelectInfoVO)array1.get(2)).getStu_num+=((SelectInfoVO)array1.get(3)).getStu_num平均值=a/b4组值比较少,可以象上面那么写,要是有N多组值,应该怎么求???哪为大侠帮我优化一下
我的数据库表里有4个学校的语文成绩和学校的考试人数,求平均值如下:
a=((SelectInfoVO)array1.get(0)).getYuwen_score()*((SelectInfoVO)array1.get(0)).getStu_num()+((SelectInfoVO)array1.get(1)).getYuwen_score()*((SelectInfoVO)array1.get(1)).getStu_num()+((SelectInfoVO)array1.get(2)).getYuwen_score()*((SelectInfoVO)array1.get(2)).getStu_num()+((SelectInfoVO)array1.get(3)).getYuwen_score()*((SelectInfoVO)array1.get(3)).getStu_num()
b=((SelectInfoVO)array1.get(0)).getStu_num+((SelectInfoVO)array1.get(1)).getStu_num
+((SelectInfoVO)array1.get(2)).getStu_num+=((SelectInfoVO)array1.get(3)).getStu_num平均值=a/b4组值比较少,可以象上面那么写,要是有N多组值,应该怎么求???哪为大侠帮我优化一下
double b=0;
for (int i=0;i<array1.size();i++){
a = a + ((SelectInfoVO)array1.get(i)).getYuwen_score()*((SelectInfoVO)array1.get(i)).getStu_num();
b = b + ((SelectInfoVO)array1.get(1)).getStu_num;
}
double 平均值=a/b;