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From: Terry Reedy <tjreedy@udel.edu>
Subject: Re: zip as iterator and bad/good practices
Date: Fri, 12 Jun 2015 19:27:44 -0400
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Xref: csiph.com comp.lang.python:92566

On 6/12/2015 11:00 AM, Fabien wrote:
> is it a bad practice
> to interactively modify the list you are iterating over?

One needs care.  Appending to the end of the list is OK, unless you 
append a billion items or so ;-)  Appending to the end of a queue while 
*removing* items from the front of the queue, where the queue resizes 
itself at the front as needed, is standard for breadth-first search.  A 
deque.Deque can be used for this.  Depth-first search appends to and 
deletes from the end (or top) of a stack, but this is NOT 
forward-iteration as implemented by Python iterators.

-- 
Terry Jan Reedy