How to put back a number-based index

David Shi davidgshi at yahoo.co.uk
Fri May 13 16:11:35 EDT 2016


Dear Michael,
I have done a number of operation in between.
Providing that information does not help you
How to reset index after grouping and various operations is of interest.
How to type in a command to find out its current dataframe?
Regards.
David 

    On Friday, 13 May 2016, 20:58, Michael Selik <michael.selik at gmail.com> wrote:
 

 Just in case I misunderstood, why don't you make a little example of before and after the grouping? This mailing list does not accept attachments, so you'll have to make do with pasting a few rows of comma-separated or tab-separated values.
On Fri, May 13, 2016 at 3:56 PM Michael Selik <michael.selik at gmail.com> wrote:

In order to preserve your index after the aggregation, you need to make sure it is considered a data column (via reset_index) and then choose how your aggregation will operate on that column.
On Fri, May 13, 2016 at 3:29 PM David Shi <davidgshi at yahoo.co.uk> wrote:

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, ?).

 



   


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