AZ
data.groupby("customer")["amount"].sum()
Size: a a a
AZ
data.groupby("customer")["amount"].sum()
YU
data.groupby("customer")["amount"].sum()
AZ
data[data["customer"].isin(customer_list)].groupby("customer")["amount"].sum()
YU
AZ
А
PZ
PZ
А
PZ
А
PZ
А
А
PZ
А
А
PZ