def function(row):
    return pd.Series([row.A, row.A / 2])
df2 = pd.DataFrame({'A': np.random.randn(8), 'B': pd.date_range('1/1/2011',
    periods=8, freq='H'), 'C': np.random.randn(8)})
Pandas apply with list output gives ValueError once df contains timeseries