SAS宏变量变化+数组索引

Question

这与这个问题有关:SAS macro variable change .

下面的代码解释了这个问题:

%macro test (arg=); 
    options  mlogic mprint symbolgen;
    array arraytwo [%EVAL(&arg+1)] _temporary_;
    sum=0;
    %do i = 1 %to %EVAL(&arg+1);
        sum=sum+&i;
        arraytwo[&i]=sum;
        %end;
    return=arraytwo[&arg+1];
    %mend test;

/* This is ok */
data dat1;
    %test(arg=9);
run;

data dat2;
    input M;
    cards;
5
6
7
;
run;

/* This give an error= A character operand was found in the %EVAL function or %IF condition where a numeric
operand is required. The condition was: M+1 */
data dat3;
    set dat2;
    %test(arg=M);
run;

那么问题来了，为什么上次测试会出bug？谢谢。

Answer 1

如果您碰巧使用的是 SAS 9.2 或更高版本，您可能需要查看 proc fcmp 来创建一个函数来执行此操作。

如果将其编写为函数而不是宏，则可以传入可解析为数值的数据集变量，或直接传递数值。例如，试试这段代码:

proc fcmp outlib=work.funcs.simple;
  function sumloop(iter);
    x=1;
    do i=1 to iter+1;
      x+i;
    end;
    return(x);
  endsub;
run;

/* point to the location the function was saved in */
option cmplib=work.funcs; 

data _null_;
  input M;
  y=sumloop(M); /* data set variable */
  z=sumloop(9); /* static numeric value */
  put M= @7 y= @14 z= @20 ;
cards;
1
2
3
4
5
6
7
8
9
;
run;

/* My log looks like this:

14   data _null_;
15       input M;
16       y=sumloop(M); /* data set variable */
17       z=sumloop(9); /* static numeric value */
18       put M= @7 y= @14 z= @20 ;
19       cards;

M=1   y=3    z=55
M=2   y=6    z=55
M=3   y=10   z=55
M=4   y=15   z=55
M=5   y=21   z=55
M=6   y=28   z=55
M=7   y=36   z=55
M=8   y=45   z=55
M=9   y=55   z=55
*/