Replace Values By The Mean

I have a dataframe as follow: Col1 Price 1 Plastic 50 2 Metal 100 3 Plastic 40 I would like to replace values in Col1 by thei

Solution 1:

You are correct- map can be used to do this like so:

df['Col1'] = df['Col1'].map(df.groupby('Col1')['Price'].mean())
df
   Col1  Price
1    45     50
2   100    100
3    45     40

Solution 2:

df.assign(Col1=df.Col1.map(df.groupby('Col1').mean().squeeze()))

Output:

   Col1  Price
1    45     50
2   100    100
3    45     40

Solution 3:

If you want the result directly , You can use transform

df['Col1']=df.groupby(['Col1'])['Price'].transform('mean')


   Col1  Price
0    45     50
1   100    100
2    45     40