How can I use groupby in pandas effectively?

How can I use groupby in pandas effectively?

You can use the groupby function to split your data into groups based on some criteria, then apply functions to each group.

Can you give me an example of grouping by a column?

Sure! If you have a DataFrame with sales data, you can group by 'store' and then sum the sales like this: df.groupby('store')['sales'].sum().

What if I want to group by multiple columns?

You can pass a list of columns to groupby. For example: df.groupby(['store', 'product'])['sales'].sum() will group by both store and product.

How do I reset the index after grouping?

You can use the reset_index() method after grouping. For example: grouped = df.groupby('store')['sales'].sum().reset_index().