The Polars .group_by() method is used to create groupings based on column values and aggregate related values.Aggregation is a common technique in summarizing data, and it condenses related values into a single value.You can use .filter() to view specific data and .group_by() to summarize one or more columns in Polars.Time series data can be grouped using .group_by_dynamic() in Polars.You can match summarized data with the original data using window functions in Polars.Pivot tables in Polars allow you to group and aggregate rows and columns of data efficiently.To start with grouping data in Polars, you need to have a familiarity with Polars DataFrames or similar libraries like pandas.Install the Polars library using the command 'python -m pip install polars' to begin working with Polars in Python.In Polars, you can aggregate data by applying aggregation functions directly to the columns of interest.To find the highest number of absences among students in the math class, you can use aggregation functions provided by Polars.