selecting from multi-index pandas

Question

I have a multi-index data frame with columns \'A\' and \'B\'.

Is there is a way to select rows by filtering on one column of the multi-index without resetting the

Answer 1

One way is to use the get_level_values Index method:

In [11]: df
Out[11]:
     0
A B
1 4  1
2 5  2
3 6  3

In [12]: df.iloc[df.index.get_level_values('A') == 1]
Out[12]:
     0
A B
1 4  1

In 0.13 you'll be able to use xs with drop_level argument:

df.xs(1, level='A', drop_level=False) # axis=1 if columns

Note: if this were column MultiIndex rather than index, you could use the same technique:

In [21]: df1 = df.T

In [22]: df1.iloc[:, df1.columns.get_level_values('A') == 1]
Out[22]:
A  1
B  4
0  1