Find equal columns between two dataframes

Question

I have two pandas data frames, a and b:

a1   a2   a3   a4   a5   a6   a7
1    3    4    5    3    4    5
0    2    0           


        

Answer 1

Here's one way leveraging broadcasting to check for equality between both dataframes and taking all on the result to check where all rows match. Then we can obtain indexing arrays for both dataframe's column names from the result of np.where (with @piR's contribution):

i, j = np.where((a.values[:,None] == b.values[:,:,None]).all(axis=0))
dict(zip(a.columns[j], b.columns[i]))
# {'a7': 'b2', 'a6': 'b3', 'a4': 'b4', 'a2': 'b7'}