How to put back a number-based index

Fri May 13 15:27:14 EDT 2016

Hello, Michael,
Why reset_index before grouping?
Regards.
David 

    On Friday, 13 May 2016, 17:57, Michael Selik <michael.selik at gmail.com> wrote:

On Fri, May 13, 2016 at 12:27 PM David Shi via Python-list <python-list at python.org> wrote:

I lost my indexes after grouping in Pandas.
I managed to rest_index and got back the index column.
But How can I get back a index row?

Was the grouping an aggregation? If so, the original indexes are meaningless. What you could do is reset_index before the grouping and when you aggregate decide how to handle the formerly-known-as-index column (min, max, mean, ?).