how to get a subgroup start finish indexes of dataframe

5

df=pd.DataFrame({"C1":['USA','USA','USA','USA','USA','JAPAN','JAPAN','JAPAN','USA','USA'],'C2':['A','B','A','A','A','A','A','A','B','A']})

    C1      C2
0   USA     A
1   USA     B
2   USA     A
3   USA     A
4   USA     A
5   JAPAN   A
6   JAPAN   A
7   JAPAN   A
8   USA     B
9   USA     A

This is a watered version of my problem so to keep it simple, my objective is to iterate a sub group of the dataframe where C2 has B in it. If a B is in C2 - I look at C1 and need the entire group. So in this example, I see USA and it starts at index 0 and finish at 4. Another one is between 8 and 9.

So my desired result would be the indexes such that:

[[0,4],[8,9]] 

I tried to use groupby but it wouldn't work because it groups all the USA together

my_index = list(df[df['C2']=='B'].index)
my_index

woudld give 1,8 but how to get the start/finish?

python pandas

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asked Apr 18 at 16:17

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