I have a dataframe(df):

```
         id  CI    VaR
0        1  0.600  1000
1        1  0.650  1100
2        1  0.700  1200
3        1  0.750  1300
4        2  0.600  2500
5        2  0.650  2600
6        2  0.700  2700
7        2  0.750  2800
8        3  0.600  1500
9        3  0.650  1600
10       3  0.700  1700
11       3  0.750  1800

```

i have to create a subset dataframe from this dataframe
im doing this;

```
for col in range(1,4):
    df2 = df1.loc[df1["id"]==col]
    print(df2)

```

output:

```
         id  CI    VaR
0        1  0.600  1000
1        1  0.650  1100
2        1  0.700  1200
3        1  0.750  1300

```

and

```
4        2  0.600  2500
5        2  0.650  2600
6        2  0.700  2700
7        2  0.750  2800

```

and

```
8        3  0.600  1500
9        3  0.650  1600
10       3  0.700  1700
11       3  0.750  1800

```

this will give me separate dataframe for id 1,2,3
Now i want to VaR value of all dataframe(1 ,2 and 3) and add all the value in the order they are and append to the dataframe of respective.
like:

```
obj = 0
for col in range(1,4):
    df2 = df1.loc[df1["id"]==col]
    obj = obj + df1["VaR"] # error is here
    print(df2)

```

But this is not working for me

i need ouput like ;

```
         id  CI    VaR   capital
0        1  0.600  1000  5000
1        1  0.650  1100  5300
2        1  0.700  1200  5600
3        1  0.750  1300  5900

```

capital value 5000 came from adding 1000 + 2500 + 1500 ( these are all first value of respecti id)
capital value 5300 came from adding 1100 + 2600 + 1600 ( these are all second value of respecti id)
and so on ...
and i need for all the id's
like;

```
4        2  0.600  2500   5000
5        2  0.650  2600   5300
6        2  0.700  2700   5600
7        2  0.750  2800   5900

```

and

```
8        3  0.600  1500   5000
9        3  0.650  1600   5300
10       3  0.700  1700   5600
11       3  0.750  1800   5900

```

Thanks for your time :)