pandas - filter dataframe by another dataframe by row elements

Question

I have a dataframe df1 which looks like:

   c  k  l
0  A  1  a
1  A  2  b
2  B  2  a
3  C  2  a
4  C  2  d

and another called

Answer 1

This is pretty succinct and works well:

df1 = df1[~df1.index.isin(df2.index)]