filter4dABSTRACT Lappeenranta University of Technology Department of Mathematics and Physics Idrissa S. Amour On Variational Ensemble Kalman Filtering Thesis for the Degree of Master ofMethod 2 – Use the Excel FILTER Function to Extract Data Based on a Data Validation Drop Down List. If you are working in Excel 2019 and later versions or in Microsoft 365, you can filter data using the FILTER function..