编写无放回取数程序

熟悉SAS自带的 能满足个人需求的 过程 固然很重要
但是自己写代码 实现目的 更能锻炼人
有时一段优秀的代码 速度要比SAS过程步 效率高很多

1. 有时一段优秀的代码 速度要比SAS过程步 效率高很多

复制代码

Just my personal point of view:
PROC SURVEYSELECT specializes in sample selection.  It meets different needs on sampling. As a statistician, it is no reason for avoiding those credible procedures SAS has provided for instead of the preliminary self-programming.

data a;
sampsize=10;        /*sampsize表示所要取的值的number*/
obsleft=totobs;             /*obsleft表示还需要取值的个数，totobs所取值的总数 */
do while(sampsize>0 and obsleft>0);
pickit+1;                       /*pickit表示 the number of observation to
                                 be read in the sample data set.Its starting value is 0 */

if ranuni(0)<sampsize/obsleft then
do ;
set proii3.sale2000 point=pickit nobs=totobs;
output;
sampsize=sampsize-1;
end;
obsleft=obsleft-1;
end;
stop;
run;

very good, not very easy

不错，学习学习。

qzuxwj138 发表于 2009-12-31 15:22
data a;
sampsize=10;        /*sampsize表示所要取的值的number*/
obsleft=totobs;             /*obsle ...

不太明白哎,这样怎么实现不放回了呢?麻烦点拨下.

PROC SURVEYSELECT seems cool
Thanks, jingju11 and yongyitian!