How can I combine two pandas data frames together? They don't share a common column so it seems that merge isn't an option and I lose rows with concat. I want to do something like this
df1= df2= df3 = df1+df2
A B C D E F A B C D E F
1 2 3 1 2 3 1 2 3 1 2 3
4 5 7 4 5 6 4 5 6 4 5 6
8 9 10 8 9 10