Set difference in Pandas
I posted this question <a href="http://stackoverflow.com/questions/18180763/set-difference-for-pandas/18187648?noredirect=1">set difference for pandas</a> in SO but the answer I received produces some loss of precision. 

The basic idea is that if you have two dataframes df1, df2, you should be able to get the rows in df1 that are not included in df2. That is, the set difference of df1 and df2.

I think this would be a good feature request in case it's not possible to solve this easily using Panda's current capabilities 
