How to sum a range of values in one column based on a range as defined by a multiindex

Question

I'm well and truly stumped on this

I have a MultiIndex dataframe that looks like this

               data
index1 index2  
0      1       8
       2       7
       3       6
       4       9
1      1       3
       2       4
       3       3
       4       6
2      1       5
       2       5

.... and so on

and I'm trying to sum a load of values from the data column for each index1 based on a range of values from index2 to create a new dataframe.

i.e. if I were to create a new dataframe from the data values that correspond to the first 2 values of index2 per index1 from the example above I would want to get,

index1 summed_data
0      15
1      7
2      10

Does anyone know how to do this?

Answer 1

You don't need to change your input format, using the following statement：

x = df.groupby(level ='index1').agg({'data': lambda x: x[:2].sum()}).rename(columns = {'data':'summed_data'})

Then print：

        summed_data
index1             
0                15
1                 7
2                10