I am trying to count how many orders there was for each product, by using the line of code below

TSP_Order = TSP_Order.groupby(['ProdName','Year']).count('OrderID')

But i receive the error below TypeError: count() takes 1 positional argument but 2 were given

An example of my dataset

I want to calculate how many times each product was ordered per year.

CodePudding user response：

You were almost there. After grouping on the fields of interest, you need to access the column of interest, here OrderID, and perform the statistic you need (simple count in this case):

df.groupby(['ProdName','Year'])['OrderID'].count()

ProdName   Year
Puzzle     2015    1
           2016    1
Toy Car    2015    2
           2016    2
Train Set  2015    1
           2016    1
Name: OrderID, dtype: int64

with

df

    ProdName  OrderID  Year
0    Toy Car        1  2015
1     Puzzle        1  2015
2    Toy Car        2  2015
3  Train Set        2  2015
4    Toy Car        3  2016
5     Puzzle        4  2016
6    Toy Car        5  2016
7  Train Set        5  2016