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From: Terry Reedy <tjreedy@udel.edu>
Subject: Re: Interpreting Left to right?
Date: Fri, 24 Jun 2011 20:56:58 -0400
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:8424

On 6/24/2011 5:08 PM, Tycho Andersen wrote:

> "An assignment statement evaluates the expression list (remember that
> this can be a single expression or a comma-separated list, the latter
> yielding a tuple) and assigns the single resulting object to each of
> the target lists, from left to right."

This is the 'other' type of 'multiple assignment'

a,b,c = 1,2,3

Order matters here too.

a,a[1] = [1,2],3
a
# [1,3]
# but

a[1], a = 3, [1,2]
will either fail or modify what a was previously bound to before 
rebinding a to [1,2].

-- 
Terry Jan Reedy