sas programming by example chapter3.1?

shiyiming

data all (keep=DOB ID Salary);
Merge one two three;
by ID;
run;
proc print;
run;
Data all;
set one (drop=sex);
two (keep=ID DOB Salary);
three(keep=ID DOB Salary);
proc print;
run;
输出的结果顺序是：DOB ID Salary,不是ID DOB Salary. 什么原因呢？

shiyiming

可能是应为变量的内部顺序。
只要在proc print的时候指定顺序即可。
[code:bb3f4]proc print data=all;
var ID DOB Salary;
run;[/code:bb3f4]

shiyiming

呵呵,这个问题是由于keep的三种出现情况的影响时效是不一样的.
1.做为输出数据集的DATASET OPTION
2.做为输入数据的DATASET OPTION
3.做为数据步中的KEEP STATEMENT
大家自己研究帮助吧. <!-- s:oops: --><img src="{SMILIES_PATH}/icon_redface.gif" alt=":oops:" title="Embarassed" /><!-- s:oops: -->