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From: Paul Appleby <pap@nowhere.invalid>
Newsgroups: comp.lang.python
Subject: Re: So what's happening here?
Date: Fri, 5 Jun 2015 13:11:13 +0000 (UTC)
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On Fri, 05 Jun 2015 14:55:11 +0200, Todd wrote:

> Numpy arrays are not lists, they are numpy arrays. They are two
> different data types with different behaviors.  In lists, slicing is a
> copy.  In numpy arrays, it is a view (a data structure representing some
> part of another data structure).  You need to explicitly copy the numpy
> array using the "copy" method to get a copy rather than a view:

OK, thanks.  I see. 

(I'd have thought that id(a[1]) and id(b[1]) would be the same if they 
were the same element via different "views", but the id's seem to change 
according to rules that I can't fathom.)