熊猫数据框按修改后的索引分组

Question

I have following panda data-frame and I am trying to group it by Index1 column values after extracting the right hand side of the dash sign, ie, z and y.

Index1  Index2  Value
 a-z    1       10
 a-z    2       10
 a-z    1       4
 c-z    2       5
 c-z    1       9
 c-z    2       6
 a-z    1       6
 a-y    2       7
 b-y    1       8
 b-y    2       2
 c-y    1       9
 c-y    2       4

So the final result after using group-by sum should be something like this:

Index1  Index2  Value
z       1       29
z       2       21
y       1       17
y       2       13

Thanks a lot for your help.

Answer 1

You can use:

df.groupby([df['Index1'].str[-1], df['Index2']])['Value'].sum().reset_index()

Output:

   Index1   Index2  Value
0    y        1      17
1    y        2      13
2    z        1      29
3    z        2      21