Modifying dataFrames inside a list is not working

Question

I have two DataFrames and I want to perform the same list of cleaning ops. I realized I can merge into one, and to everything in one pass, but I am still curios

Answer 1

By using pd.concat

[x.reset_index(level=0,drop=True) for _, x in pd.concat([test_1,test_2],keys=[0,1]).dropna().groupby(level=0)]
Out[376]: 
[     A   B
 0  1.0  15
 1  8.0  49
 2  5.0  34
 3  6.0  44
 4  0.0  63,      A    B
 1  3.0  100
 2  6.0  200
 3  4.0  300
 4  9.0  400
 5  0.0  500]