I've got a dataframe of the following pattern:
Date Item Purchased
01/01/08 Fruit 48
01/01/08 Confectionary 42
01/01/08 Appliance 11
01/06/08 Confectionary 16
01/06/08 Fruit 19
01/06/08 Appliance 50
What I'd like to do is sum by date the total number of items sold on that day, as a row under the 'Item' column, maybe with the name 'Overall' or something. So 01/01/08 will have 4 rows with that date, one titled 'Overall' with '101' in the 'Purchased' column. Thanks for any assistance/advice.