[FIXED] How to get list of mean values of sale for 45 stores

Issue

filt=Q3_df['Store']=1;

Q3_df.loc[filt,'Weekly_Sales'].mean()

# >>>output=1555264.3975524479

# Q3_df  dataset#
Store   Weekly_Sales
                
  1  1643690.90 
  1  1641957.44 
  1  1611968.17 
  1  1409727.59 
  1  1554806.68 
  ...   ... ... ... 
  45    713173.95   
  45    733455.07   

Solution

Are you looking for a groupby aggregation?

Q3_df.groupby(Q3_df.index)[['Weekly_Sales']].mean()

Just to articulate with a small example:

import pandas as pd

Q3_df = pd.DataFrame({"Store":[1,1,2,2,3,3], "Weekly_Sales":list(range(6))})

If Store is not the index:

Q3_df.groupby(["Store"])[["Weekly_Sales"]].mean()

If Store is the index:

Q3_df.set_index("Store", inplace=True)

Q3_df.groupby(Q3_df.index)[["Weekly_Sales"]].mean()

With this specific example, they both give:

       Weekly_Sales
Store
1               0.5
2               2.5
3               4.5

If Store is the index, you can assign those mean values to a new column:

Q3_df.assign(mean_values=Q3_df.groupby(Q3_df.index)[["Weekly_Sales"]].mean())

OUTPUT

       Weekly_Sales  mean_values
Store
1                 0          0.5
1                 1          0.5
2                 2          2.5
2                 3          2.5
3                 4          4.5
3                 5          4.5

Answered By - nikeros