ENH: merge multi-index with a multi-index #6360
Description
#3662 is about merging a single-level index with a mi
This is is about a multi-multi merge
# example described there: In [11]: df = pd.DataFrame(np.random.randn(10,5)) ...: df1 = df[range(0, 3)].set_index([0, 2]) ...: df2 = df[range(2, 5)].set_index([2, 4]) ...: res = df1.join(df2, how='inner') # empty. Do I need to specify something here? ...: exp = pd.DataFrame({1: df[1], 3: df[3]}) ...: exp.index = df[2]