如何在if语句中创建数组

Posted 2023-02-19

【中文标题】如何在if语句中创建数组

【英文标题】：How to create array in if statement

【发布时间】：2022-01-14 23:57:13

【问题描述】：

我想复制和修改表中的特定行。

之前：

xyz_id | letter | Col_1 | ...|
1 | Z | V1 | ... |
2 | Z | V2 | ... |
3 | Z | V3 | ... |

之后：

xyz_id | letter | Col_1 | ...|
1 | A | V1.1 | ... |
1 | B | V1.2 | ... |
1 | C | V1.3 | ... |
2 | A | V2.1 | ... |
2 | B | V2.2 | ... |
2 | C | V2.3 | ... |
3 | A | V3.1 | ... |
3 | B | V3.2 | ... |
3 | C | V3.3 | ... |

我已经准备了以下代码：

data test2;
        set test;

        
        array letters 3 $3 _temporary_ ('A', 'B', 'C');
        array weights 3  _temporary_ (1,2,3);

/*      if xyz_id = '1' */
/*          then  array weights 3  _temporary_ (1,2,3);*/
/*      else if xyz_id = '2'*/
/*          then array weights 3  _temporary_ (8,7,6);*/
/*      else array weights 3  _temporary_ (1,1,1)*/


        do i = 1 to 8;
            letter = letters(i);
            Col_A = Col_A * weights(i);
            output;
        end;
          drop i;
run;

现在，我正在尝试使 weights 依赖于 letter 列（注释代码） - 但没有任何成功。我也试过了：

   array weights_1 3  _temporary_ (1,2,3);
   if xyz_id = '1'
            then  weights = weights_1;

但效果不佳。

有什么建议吗？

【参考方案1】：

需要添加一个 3D 数组。

array weights3,3  
                            c1_w1-c1_w8
                            c2_w1-c2_w8
                            c3_w1-c3_w8 
                                (
                                0.1 0.1   /*letter 1*/
                                1 22 23   /*letter 2*/
                                1 32 33   /*letter 3*/
                                );

所以最后的代码是：

data test2;
        set test;

        
        array letters 3 $3 _temporary_ ('A', 'B', 'C');
        array weights 3  _temporary_ (1,2,3);



            if xyz_id = '1' 
                then  weights_dim=1;
            else if xyz_id = '2' 
                then  weights_dim=2;
            else if xyz_id = '3' 
                then  weights_dim=3;

        weight = weightsweights_dim, i;

        do i = 1 to 8;


            letter = letters(i);
            Col_A = Col_A * weight;
            output;
        end;
          drop i;
run;

【参考方案2】：

怎么样

data have;
input xyz_id letter  $ Col_1 $;
datalines;
1 Z V1 
2 Z V2 
3 Z V3 
;

data want;
  set have;

  array letters 3 $3 _temporary_ ('A', 'B', 'C');
  array weights 3    _temporary_ (1,2,3);

  c = Col_1;

  do i = 1 to 3;
      letter = letters[i];
      Col_1  = catx('.', c, weights[i]);
      output;
  end;
  
  drop i c;
run;