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From: Michael Selik <michael.selik@gmail.com>
Newsgroups: comp.lang.python
Subject: Re: Pandas GroupBy does not behave consistently
Date: Sun, 15 May 2016 19:03:28 +0000
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On Sun, May 15, 2016 at 7:07 AM David Shi <davidgshi@yahoo.co.uk> wrote:

> Hello, Michael,
>
> Pandas GroupBy does not behave consistently.
>
> Last time, when we had conversation, I used grouby.  It works well.
>
> Now, I thought to re-write the program, so that I can end up with a clean
> script.
>
> But, the problem is that a lot of columns are missing after groupby
> application.
>
> Any idea?
>

I'd guess that the columns lost after a groupby had an inappropriate
datatype for the operation you were doing. If you'd like a more thorough
response, you'll need to post the code you tried and the results you got.