删除"开始"之前和"结束"之后的观察 - SAS 代码

Question

我的表有一些我试图删除的前导和尾随观察。我想删除每个组的每个"开始"事件之前和每个"结束"事件之后的行。该表类似于以下内容：

| Time | Group | Event | Value  |
|   1  |    1  | NA    |      0 |
|   2  |    1  | NA    |      0 |
|   3  |    1  | Begin |    1.1 |
|   4  |    1  | NA    |    1.2 |
|   5  |    1  | NA    |    1.3 |
|   6  |    1  | End   |    1.4 |
|   7  |    1  | NA    |      0 |
|   1  |    2  | NA    |      0 |
|   2  |    2  | Begin |    1.1 |
|   3  |     2 | NA    |    1.2 |
|   4  |     2 | End   |    1.3 |
|   5  |     2 | NA    |    1.4 |

Answer 1

假设传入数据已经排序，并且每个组中有零个或多个"开始到结束"的串行边界范围：

data want;
  do until (last.group);
    set have;
    by group time;
    if event = 'Begin' then _keeprow = 1;
    if _keeprow then output;
    if event = 'End' then _keeprow = 0;
  end;
  drop _keeprow;
end;

Answer 2

我提出了一个简单的方法，但会受到实际数据大小的限制。

data have;
input  Time  Group  Event $ Value  ;
datalines;
1      1   NA          0 
2      1   NA          0 
3      1   Begin     1.1 
4      1   NA        1.2 
5      1   NA        1.3 
6      1   End       1.4 
7      1   NA          0 
1      2   NA          0 
2      2   Begin     1.1 
3       2  NA        1.2 
4       2  End       1.3 
5       2  NA        1.4 
;
run;
proc sort data = have;
     by group time;
run;
data have1;
     set have;
     count + 1;
     by group;
     if first.group then count = -100;
     if event = 'Begin' then count = 0;
     if event = 'End' then count = 100;
     if count < 0 or count >100 then delete;
run;

如果"开始"和"结束"之间的观测值少于 100

个，并且在"开始"之前观测值少于 100 个，则当前代码可以应用于小型数据。您可以根据真实数据大小调整初始计数值。

Answer 3

一种方法是

data have;
input  Time  Group  Event $ Value  ;
datalines;
1      1   NA          0 
2      1   NA          0 
3      1   Begin     1.1 
4      1   NA        1.2 
5      1   NA        1.3 
6      1   End       1.4 
7      1   NA          0 
1      2   NA          0 
2      2   Begin     1.1 
3       2  NA        1.2 
4       2  End       1.3 
5       2  NA        1.4 
;

 data have2(keep= Group min_var max_var);
    set have;
   by group;
   retain min_var max_var;
     if trim(Event)= "Begin" then min_var =_n_ ;
       if trim(Event)= "End" then max_var =_n_;
      if last.group;
       run;
       data want;
          merge have have2;
       by group;
       if _n_  ge min_var and _n_  le max_var ;
         drop min_var max_var;
        run;