pandas: how to run a pivot with a multi-index?

Question

I would like to run a pivot on a pandas DataFrame, with the index being two columns, not one. For example, one field for the year, one for the month, an \'item\

Answer 1

thanks to gmoutso comment you can use this:

def multiindex_pivot(df, index=None, columns=None, values=None):
    if index is None:
        names = list(df.index.names)
        df = df.reset_index()
    else:
        names = index
    list_index = df[names].values
    tuples_index = [tuple(i) for i in list_index] # hashable
    df = df.assign(tuples_index=tuples_index)
    df = df.pivot(index="tuples_index", columns=columns, values=values)
    tuples_index = df.index  # reduced
    index = pd.MultiIndex.from_tuples(tuples_index, names=names)
    df.index = index
    return df

usage:

df.pipe(multiindex_pivot, index=['idx_column1', 'idx_column2'], columns='foo', values='bar')

You might want to have a simple flat column structure and have columns to be of their intended type, simply add this:

(df
   .infer_objects()  # coerce to the intended column type
   .rename_axis(None, axis=1))  # flatten column headers