Pandas: drop a level from a multi-level column index?

Question

If I've got a multi-level column index:

>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ("a", "c")]) >>> pd.DataFrame([[1,2], [3,4]], columns=cols) 

     a    ---+--     b | c --+---+-- 0 | 1 | 2 1 | 3 | 4 

How can I drop the "a" level of that index, so I end up with:

     b | c --+---+-- 0 | 1 | 2 1 | 3 | 4 

Answer 1

You can use MultiIndex.droplevel:

>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ("a", "c")]) >>> df = pd.DataFrame([[1,2], [3,4]], columns=cols) >>> df    a       b  c 0  1  2 1  3  4  [2 rows x 2 columns] >>> df.columns = df.columns.droplevel() >>> df    b  c 0  1  2 1  3  4  [2 rows x 2 columns]