Having trouble to sum values in a column that match a given condition

Question

I am trying to sum the numeric values of one column depending on the value of another column. For example: whenever in the first column there is a Glovoapp I would like to sum its corresponding numeric values (of another column) together.

Table example:

Initiator	Price
Glovoapp	566
XXXXX	545
Glovoapp	899
XXXXX	200

montant_init = new_data.loc[new_data['Initiateur'] == 'Glovoapp', 'Price'].sum()

output: 0 (none)
expected output (example): 1465

Answer 1

Use:

montant_init = df[df["Initiator"]=="Glovoapp"]["Price"].sum()

Alternatively you can use groupby if you have multiple Initiators:

price_sum = df.groupby("Initiator")["Price"].sum()

output:

Initiator
Glovoapp    1465
XXXXX        745

Then

price_sum["Glovoapp"]

outputs:

1465