Finding Merge (Outer - Inner) Pandas DF differences

Question

Want to find the difference between two outer-merge and inner-merge DataFrames, without finding any row with NaN -- I want to keep some rows with them. Is there a way to do this using the difference method or preferably without having to create both FrameA and FrameB ?

import pandas as pd

DataA = pd.DataFrame([{"a": 1, "b": 4}, {"a": 6, "b": 2}, {"a": 2, "b": 5}, {"a": 3, "b": 6}, {"a": 7, "b": 2}])
DataB = pd.DataFrame([{"a": 2, "d": 7}, {"a": 7, "d": 8}, {"a": 3, "d": 8}])

DataA

    a   b
0   1   4
1   6   2
2   2   5
3   3   6
4   7   2

DataB

    a   d
0   2   7
1   7   8
2   3   8

...

FrameA = pd.merge(DataA, DataB, on = "a", how ='inner')
FrameB = pd.merge(DataA, DataB, on = "a", how ='outer')

FrameA

    a   b   d
0   2   5   7
1   3   6   8
2   7   2   8

FrameB

    a   b   d
0   1   4   NaN
1   6   2   NaN
2   2   5   7
3   3   6   8
4   7   2   8

Trying to find DataFrame differences...

list(FrameB.index.difference(FrameA.index))

Maybe you have a better solution, with this desired output:

    a   b   d
0   1   4   NaN
1   6   2   NaN

Answer 1

You are looking for the symmetric_difference :

a = DataA.set_index('a')
b = DataB.set_index('a')

# select rows from the outer join using the symmetric difference (^)
a.join(b, how='outer').loc[a.index ^ b.index].reset_index()