Group By

GroupBy-এর idea:

একই category/entity-এর rows group করে aggregate করা।

Example:

df.groupby("city")["revenue"].sum()

Multiple groups:

df.groupby(
    ["city", "category"]
)["revenue"].mean()

SQL equivalent

SELECT
    city,
    SUM(revenue)
FROM sales
GROUP BY city;

GroupBy Data Science-এ daily use-এর জিনিস।