Grouping column values together

Question

I have a dataframe like so:

Class  price  demand
1       22       8
1       60       7
3       32       14
2       72       9
4       45       20
5       42       25

What I'd like to do is group classes 1-3 in one category and classes 4-5 in one category. Then I'd like to get the sum of price for each category and the sum of demand for each category. I'd like to also get the mean. The result should look something like this:

Class   TotalPrice   TotalDemand   AveragePrice  AverageDemand
P          186            38           46.5          9.5   
E          87             45           43.5          22.5

Where P is classes 1-3 and E is classes 4-5. How can I group by categories in pandas? Is there a way to do this?

Answer 1

In [8]: df.groupby(np.where(df['Class'].isin([1, 2, 3]), 'P', 'E'))[['price', 'demand']].agg(['sum', 'mean'])
Out[8]: 
  price       demand      
    sum  mean    sum  mean
E    87  43.5     45  22.5
P   186  46.5     38   9.5