How to subtract rows of one pandas data frame from another?
Consider Following:

df_one is first DataFrame
df_two is second DataFrame

Present in First DataFrame and Not in Second DataFrame
Solution: by Index

df = df_one[~df_one.index.isin(df_two.index)]

index can be replaced by required column upon which you wish to do exclusion.
In above example, I've used index as a reference between both Data Frames
Additionally, you can also use a more complex query using boolean pandas.Series to solve for above.
The operation that I want to do is similar to merger. For example, with the inner merger we get a data frame that contains rows that are present in the first AND second data frame. With the outer merger we get a data frame that are present EITHER in the first OR in the second data frame.
What I need is a data frame that contains rows that are present in the first data frame AND NOT present in the second one? Is there a fast and elegant way to do it?