SAS delete 和 return 语句

Question

我正在查看其他人的代码并尝试确定是否：

if x = y then do;
    delete;
    return;
end;

相当于：

if x = y then do;
    delete;
end;

来自关于 DELETE 的文档：

When DELETE executes, the current observation is not written to a data set, and SAS returns immediately to the beginning of the DATA step for the next iteration.

这让我相信第一个例子中的 'return' 语句没有被执行？

Answer 1

与其猜测不如测试。

创建一个包含 x/y 个值的数据集，一个满足条件，一个不满足条件。
运行数据步骤并添加 PUT 语句以便您可以跟踪日志

从log中看到执行DELETE后什么都没有，可以确认RETURN没有执行，是多余的

仅供参考 - 需要考虑的一件事 - 这种行为是否随时间发生了变化，或者代码是否发生了变化，也许这曾经有效？通常是这样。

data have;
input x y;
cards;
1 2
1 1
;;;;
run;


data demo;
set have;
if x = y then do;
    put "Record Deleted 1";
    delete;
    put "Record Deleted 2";
    return;
    
    put "Record Deleted 3";
    
end;
else put "Record Retained";

run;

日志：

 78         data demo;
 79         set have;
 80         if x = y then do;
 81             put "Record Deleted 1";
 82             delete;
 83             put "Record Deleted 2";
 84             return;
 85         
 86             put "Record Deleted 3";
 87         
 88         end;
 89         else put "Record Retained";
 90         
 91         run;
 
 Record Retained
 Record Deleted 1
 NOTE: There were 2 observations read from the data set WORK.HAVE.
 NOTE: The data set WORK.DEMO has 1 observations and 2 variables.
 NOTE: DATA statement used (Total process time):
       real time           0.00 seconds
       user cpu time       0.00 seconds
       system cpu time     0.00 seconds
       memory              798.71k
       OS Memory           24232.00k
       Timestamp           10/18/2021 10:25:05 PM
       Step Count                        39  Switch Count  2
       Page Faults                       0
       Page Reclaims                     135
       Page Swaps                        0
       Voluntary Context Switches        10
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           264

SAS delete 和 return 语句

SAS delete and return statements

sas