Pandas: Get unique MultiIndex level values by label

Pandas 0.23.0 finally introduced a much cleaner solution to this problem: the level argument to Index.unique():

In [3]: df.index.unique(level='country')
Out[3]: Index(['DE', 'FR'], dtype='object', name='country')

This is now the recommended solution. It is far more efficient because it avoids creating a complete representation of the level values in memory, and re-scanning it.

I guess u want unique values in a certain level (and by level names) of a multiindex. I usually do the following, which is a bit long.

In [11]: df.index.get_level_values('country').unique()
Out[11]: array(['DE', 'FR'], dtype=object)