纵向数据求值

1. data aaa;
   
2. input id visit x;
   
3. cards;
   
4. 1 1 3
   
5. 1 2 3
   
6. 1 3 2
   
7. 1 4 1
   
8. 1 5 0
   
9. 2 1 2
   
10. 2 2 2
    
11. 2 3 1
    
12. 2 4 0
    
13. 2 5 0
    
14. 3 1 1
    
15. 3 2 1
    
16. 3 3 1
    
17. 3 4 0
    
18. 3 5 0
    
19. ;
    
20. run;

复制代码

每个个体的值y计算如下：
0.5*(visit=1的x值+visit=2的x值)+0.5*(visit=2的x值+visit=3的x值)+0.5*(visit=3的x值+visit=4的x值)+0.5*(visit=4的x值+visit=5的x值)

最终希望得到的数据
id y
1  值
2  值
3  值
或者
id visit x y
1 1 3  .
1 2 3 .
1 3 2 .
1 4 1 .
1 5 0  值
2 1 2 .
2 2 2 .
2 3 1 .
2 4 0 .
2 5 0 值
3 1 1 .
3 2 1 .
3 3 1 .
3 4 0 .
3 5 0 .

谢谢！

proc sort data=aaa out=aaa1;
by id visit;
run;

data wanted;
set aaa1;
by id visit;
lagx=lag(x);
if first.id then call missing(lagx);
if lagx ne . then mean=mean(x,lagx);
if first.id then y=0;
  y+mean;
if last.id;
keep id y;
run;

proc sort data=aaa;
by id;
run;
data b;
set aaa;
by id;
if first.id then temp=0.5*x;
else if last.id then temp=0.5*x;
else temp=x;
run;
proc sql;
create table total as
select id,sum(temp) as y
  from b
   group by id ;
  quit;

最后的total就是你想要的结果

方法太多了