SAS新手竭诚求教代码编写(1)

昨天已经发过一个100论坛币悬赏贴，一位热心网友已经给我详细解答了那个macro代码的各个部分，我把他的答案设为最佳答案，也让大家参考学习一下。我还有几个问题求教各位。这是一个我组上在做的research,按照老板的要求和teammate的讨论，我需要往以下几个方向编代码，SAS新手在此再发两个悬赏帖竭诚向大家求教了。

Sample Data: StudentScore

StudentID	Year	Score
A	91	400
A	92	398
A	92	399
B	91	430
B	92	432
B	93	444
B	94	446
C	91	455
C	92	423
C	93	411
C	94	415
C	95	427
C	95	418

Q1. Create a variable called “inorde” which indicates whethera student’s score increased or decreased from the previous record in the data. Marka “0” for records where the student’s score was lower than the previous record.Conversely, mark a “1” for records where a student’s score was equal or higherthan the previous record. Mark a “0” for the first record of each student.

Q2. Write code to create a SAS dataset named“StudentScore2” by picking each student’s most recent score. If there aremultiple scores for the most recent year, then pick the highest one for thatyear.

Q3. Tag on the following variables to “StudentScore2” fromthe above question.

1.
HighScore: the highest score of each student. (Use“StudentScore” as the input)
2.
AvgScore: Average score for each student. (Use“StudentScore” as the input)

1. /*INPUT*/
   
2. data StudentScore;
   
3.         input StudentID $ Year Score;
   
4.         datalines;
   
5.         A 91 400
   
6.         A 92 398
   
7.         A 92 399
   
8.         B 91 430
   
9.         B 92 432
   
10.         B 93 444
    
11.         B 94 446
    
12.         C 91 455
    
13.         C 92 423
    
14.         C 93 411
    
15.         C 94 415
    
16.         C 95 427
    
17.         C 95 418
    
18.         ;
    
19. run;
    
20. 
    
21. /*Q1*/
    
22. data StudentScore;
    
23.         set StudentScore;
    
24.         by StudentID;
    
25.         retain Score_lag;
    
26.         if Score>=Score_lag then inorde='1';
    
27.         else inorde='0';
    
28.         if first.StudentID then  inorde='0';
    
29.         Score_lag=Score;
    
30.         drop Score_lag;
    
31. run;
    
32. 
    
33. /*Q2*/
    
34. proc sort data=StudentScore out=StudentScore2;
    
35.         by StudentID descending year descending Score;
    
36. run;quit;
    
37. 
    
38. data StudentScore2;
    
39.         set StudentScore2;
    
40.         by StudentID descending year descending Score;
    
41.         if first.StudentID;
    
42.         keep StudentID Score;
    
43. run;
    
44. 
    
45. /*Q3*/
    
46. proc sql;
    
47.         create table StudentScore2 as
    
48.                 select
    
49.                         a.*
    
50.                         ,max(b.score) as HighScore
    
51.                         ,avg(b.score) as AvgScore
    
52.                 from StudentScore2 a
    
53.                 inner join StudentScore b
    
54.                 on a.StudentID=b.StudentID
    
55.                 group by
    
56.                         a.StudentId
    
57.                         ,a.Score
    
58.         ;               
    
59. quit;

复制代码

yellowriver  发表于 2010-11-2 14:23

soporaeternus 发表于 2010-11-2 14:23

终于知道了，什么是秒杀。。。