标题: 求助！关于retain语句！ [打印本页] 作者: shiyiming 时间: 2004-3-12 15:22 标题: 求助！关于retain语句！ <!-- s:o --><img src="{SMILIES_PATH}/icon_surprised.gif" alt=":o" title="Surprised" /><!-- s:o --> 小弟是初学者，有如下问题请教：
<!-- s:o --><img src="{SMILIES_PATH}/icon_surprised.gif" alt=":o" title="Surprised" /><!-- s:o --> 我想实现分组累计求和，写了如下语句：
data r2;
set r1;
by tag;
if first.tag then do;
retain tturn 0;
end;
tturn+turn;
run;
但在执行时retain语句总是保留了之前的值，而并没有置初值0，
请问我该如何实现？作者: shiyiming 时间: 2004-3-12 20:25 标题: Re: 求助！关于retain语句！ [quote="hero":21da0]:o 小弟是初学者，有如下问题请教：
<!-- s:o --><img src="{SMILIES_PATH}/icon_surprised.gif" alt=":o" title="Surprised" /><!-- s:o --> 我想实现分组累计求和，写了如下语句：
data r2;
set r1;
by tag;
if first.tag then do;
retain tturn 0;
end;
tturn+turn;
run;
但在执行时retain语句总是保留了之前的值，而并没有置初值0，
请问我该如何实现？[/quote:21da0]
It's important to know that retain statement is non-executed statement and the following code may solve your problem.
proc sort data=r1;
by tag;
run;
data r2
retain tturn;
set r1;
by tag;
if first.tag then tturn=0;
tturn+turn;
if last.tag then output;
run;作者: shiyiming 时间: 2004-3-12 22:46
Please be noted that you should add a BY TAG after PROC SORT.作者: shiyiming 时间: 2004-3-13 11:14 标题: 谢谢! 谢谢楼上的两位大哥! <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: --> <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: -->