pandas: Boolean indexing with multi index

Question

There are many questions here with similar titles, but I couldn\'t find one that\'s addressing this issue.

I have dataframes from many different origins, and I want to f

Answer 1

If you transform your index 'a' back to a column, you can do it as follows:

>>> df = pd.DataFrame({'a':[1,1,1,2,2,2,3,3,3], 
                       'b':[1,2,3,1,2,3,1,2,3], 
                       'c':range(9)})
>>> filt = pd.Series({1:True, 2:False, 3:True})
>>> df[filt[df['a']].values]
   a  b  c
0  1  1  0
1  1  2  1
2  1  3  2
6  3  1  6
7  3  2  7
8  3  3  8

edit. As suggested by @joris, this works also with indices. Here is the code for your sample data:

>>> df[filt[df.index.get_level_values('a')].values]
     c
a b   
1 1  0
  2  1
  3  2
3 1  6
  2  7
  3  8