What is the purpose of the DROP and KEEP statements in a DATA step?

The purpose of the DROP and KEEP statements in a DATA step is to control which variables are written to output data sets. When using the DROP statement, you specify variables that should be excluded from the output data set, effectively hiding them in the results. Conversely, the KEEP statement explicitly specifies which variables to retain in the output. This capability allows for efficient management of data by ensuring that only the necessary variables are retained in the final output data set, thereby improving readability and usability of the data.

Understanding this function is important in data management, as it helps in reducing clutter by removing unnecessary variables that may not be relevant, which can play a crucial role in data analysis and reporting. It streamlines the output data set by ensuring it contains only the required information for further processing or analysis.