在日常数据处理中,缺失值时时刻刻伴随着我们。对于缺失值得处理有很多的技巧。。在这里我先粗略介绍一下再SAS中如何将缺失值转换成某一个特定的字符。一般来说借助数组我们可以达到比较理想的效果。
- *step1:data prepare;
- data class;
- set sashelp.class;
- if _n_=1 then do;
- Name="";
- Weight=.;
- end;
- if _n_=2 then do;
- Sex="";
- Height=.;
- end;
- run;
- * For numeric;
- data Num_missing;
- set class;
- array Nums[*] _numeric_;
- do i = 1 to dim(Nums);
- if Nums[i] =. then Nums[i] =0;
- end;
- drop i;
- run;
- *For char missing;
- data Char_missing;
- set class;
- array Chars[*] _character_;
- do i = 1 to dim(Chars);
- if Chars[i]="" then Chars[i] = "null";
- end;
- drop i;
- run;
- data Covert_missing;
- set class;
- array Chars _character_;
- array Nums _numeric_;
- do over Chars;
- if Chars eq"" then Chars ="null";
- end;
-
- do over Nums;
- if Nums eq . then Nums =0;
- end;
- run;