GroupBy(_ => 1) code example

Example 1: groupby as_index=false

When you use as_index=False , you indicate to groupby() that you don't want to set the column ID as the index (duh!). ... Using as_index=True allows you to apply a sum over axis=1 without specifying the names of the columns, then summing the value over axis 0.

Example 2: pandas groupby

data.groupby('month', as_index=False).agg({"duration": "sum"})