BUG: multi-index to_native_types is not passing thru parameters by nbonnotte · Pull Request #11551 · pandas-dev/pandas (original) (raw)

Even when there is a third column 'c' that stays outside the index, we still get an empty Float64Index:

In [5]: pd.DataFrame({'a': np.NaN, 'b':[2,3], 'c' : [5,6]}).set_index(['a','b']).index
Out[5]: 
MultiIndex(levels=[[], [2, 3]],
           labels=[[-1, -1], [0, 1]],
           names=[u'a', u'b'])

In [6]: pd.DataFrame({'a': np.NaN, 'b':[2,3], 'c' : [5,6]}).set_index('a').index
Out[6]: Float64Index([nan, nan], dtype='float64', name=u'a')

If this is an "edge case", I'm pushing what I have done so far:

• what's new
• a short explanation for the test for date_format
• add names=self.names where it should be
• test if quoting is also passed to the multi-indexes

What I have NOT done:

• test if decimal, float_format (issue DataFrame.to_csv ignores some formatting parameters for float indexes #11553), and na_rep are passed