How can you identify unique values in a dataset using SAS?

Identifying unique values in a dataset is essential for data analysis and can be accomplished effectively using SAS tools. The correct approach involves utilizing PROC SORT with the NODUPKEY option. This method sorts the dataset and simultaneously eliminates duplicate records based on the specified key variable(s). When this procedure is invoked with NODUPKEY, SAS scans through the sorted data and retains only the first occurrence of each unique key, discarding subsequent duplicates.

This approach is efficient for quickly generating a new dataset containing only the unique values based on specified criteria. Using PROC SORT is not just about ordering data; when combined with options like NODUPKEY, it becomes a powerful tool for data cleaning and preparation.

The other methods mentioned do not serve the same purpose. The RANUNI function is used for generating random numbers, which does not relate to identifying unique values. PROC PRINT is primarily used for displaying datasets and does not alter the dataset to remove duplicates. While the DATA step can manipulate datasets, it does not intrinsically provide a built-in mechanism for identifying and removing duplicates unless combined with other procedures or programming logic. Thus, PROC SORT with the NODUPKEY option stands out as the most straightforward and effective method for identifying unique values in SAS.