Modular Arithmetic in Data Science

Modular arithmetic is a mathematical system where numbers cycle back after reaching a value called the modulus, similar to a clock. In data science, it is used for feature engineering to encode cyclical features like hours of the day, allowing machine learning models to correctly interpret temporal proximity. Another significant application is in distributed database systems for resharding, where it helps efficiently map data from an old number of shards to a new one by solving linear congruences. The content provides conceptual explanations and Python code for solving these congruences and implementing the feature engineering techniques.