pandas groupby two data frames code example

Example 1: pandas new df from groupby

df = pd.DataFrame(old_df.groupby(['groupby_attribute'])['mean_attribute'].mean())
df = df.reset_index()
df

Example 2: group by pandas examples

>>> n_by_state = df.groupby("state")["state"].count()
>>> n_by_state.head(10)
state
AK     16
AL    206
AR    117
AS      2
AZ     48
CA    361
CO     90
CT    240
DC      2
DE     97
Name: last_name, dtype: int64

Example 3: python groupby sum single columns

df.groupby(['A','C'], as_index=False)['B'].sum()

Example 4: pandas sum group by

df.groupby(['Fiscal_Year','Billing_Group'])['CHARGE_AMT'].sum()