Subset and Loop to create a new column

Asked Mar 13 '18 at 07:31

Active Mar 13 '18 at 07:31

Viewed 19 times

Good Morning,

I have the following dataset:

print(df)

Product_code   Quantity_in_stock   
    01                4                     
    02                1                   
    01                2                   
    03                6                   
    02                9                    
...

I would like to create an additional column "Average_quantity", using Pandas, equals to the average "Quantity_in_stock" of that specific product; for instance:

Product_code   Quantity_in_stock    Average_quantity
    01                4                    3  
    02                1                    5
    01                2                    3
    03                6                    6
    02                9                    5
...

I tried:

for i in df["Product_code"]:
    df["Average_quantity"] = np.mean(df["Quantity_in_stock"])

But it reports the same average quantity of the whole set, not the one of that specific product code

How Can I solve it?

asked Mar 13 '18 at 07:31

Alessandro Ceccarelli

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I think need `df['Average_quantity'] = df.groupby(['Product_code'])['Quantity_in_stock'].transform('mean')`, it is dupe. – jezrael Mar 13 '18 at 07:33
It works, thank you :) @jezrael – Alessandro Ceccarelli Mar 13 '18 at 08:06
You are welcome! – jezrael Mar 13 '18 at 08:07

Subset and Loop to create a new column

0 Answers0