What is filter?

In technology, a 'filter' is a process or component that selectively removes or modifies certain aspects of an input signal or data stream. Filters are used extensively in various applications, including: 1) Signal Processing: Removing noise or unwanted frequencies from audio or image signals. 2) Data Analysis: Filtering data based on specific criteria to isolate relevant information. 3) Network Security: Firewalls use filters to block malicious network traffic. 4) Search Engines: Applying filters to refine search results. 5) Software Development: Used in stream processing frameworks.