This code is written in SAS (Statistical Analysis System) and...

This code is written in SAS (Statistical Analysis System) and is used for conditional appending or creating a dataset based on whether the target dataset (&outds) already exists.

Here’s what the code does:

1. Check if the dataset &outds exists:

   • The macro %sysfunc(exist(&outds)) checks if the dataset specified by the macro variable &outds exists.
   • If it exists, the result is 1, and the code inside the first %do block is executed.
   • If it does not exist, the result is 0, and the code inside the %else %do block is executed.

2. First Case (&outds exists):

   proc append base=&outds data=&cnt_ds force;
   run;
   

   • If &outds exists, the PROC APPEND procedure appends the dataset specified by &cnt_ds to the existing dataset (&outds).
   • The force option ensures that the append operation proceeds even if the variables between the datasets do not perfectly match (e.g., in structure or attributes).

3. Second Case (&outds does not exist):

   data &outds;
       set &cnt_ds;
   run;
   

   • If &outds does not exist, the code creates a new dataset with the name &outds using the DATA step.
   • The SET statement reads and copies all observations from the dataset &cnt_ds into the dataset &outds.

Summary:

• If the target dataset &outds already exists, it appends the contents of &cnt_ds to &outds.
• If the target dataset &outds does not exist, it creates &outds and populates it with the contents of &cnt_ds.