Selection with a MultiIndex – a DataFrame

A pd.MultiIndex can be used both as a row index and a column index, and selection via pd.DataFrame.loc works with both.

How to do it

Let’s create a pd.DataFrame that uses a pd.MultiIndex in both the rows and columns:

row_index = pd.MultiIndex.from_tuples([
    ("John", "Smith"),
    ("John", "Doe"),
    ("Jane", "Doe"),
    ("Stephen", "Smith"),
], names=["first_name", "last_name"])
col_index = pd.MultiIndex.from_tuples([
    ("music", "favorite"),
    ("music", "last_seen_live"),
    ("art", "favorite"),
], names=["art_type", "category"])
df = pd.DataFrame([
   ["Swift", "Swift", "Matisse"],
   ["Mozart", "T. Swift", "Van Gogh"],
   ["Beatles", "Wonder", &quot...