[Chicago] I don't get why this works

[Brantley Harris]

So it evaluates the right, then left to right.  That's strange.


On Mon, Apr 1, 2013 at 10:46 PM, Alex Gaynor <alex.gaynor at gmail.com> wrote:

> Sorry, I should have been more precise, first the far right hand side is
> evaluated, so you get the string 'b' (of course). Then the assignments are
> evaluated left to right.
>
> So first:
>
> a['a'] = 'b'
>
> Then
>
> a[a['a']] = 'b'
>
> Now a['a'] == 'b'
>
> so a['b'] = 'b'.
>
> Alex
>
>
> On Mon, Apr 1, 2013 at 8:41 PM, Brantley Harris <deadwisdom at gmail.com>wrote:
>
>> Okay, then it should be a key error:
>>
>> > a['a'] = a[a['a']]
>> KeyError: 'a'
>>
>>
>> On Mon, Apr 1, 2013 at 10:25 PM, Alex Gaynor <alex.gaynor at gmail.com>wrote:
>>
>>> The assignments are going left to right.
>>>
>>> Alex
>>>
>>>
>>> On Mon, Apr 1, 2013 at 8:24 PM, Brantley Harris <deadwisdom at gmail.com>wrote:
>>>
>>>> > a = {}
>>>> > a['a'] = a[a['a']] = 'b'
>>>> {'a': 'b', 'b': 'b'}
>>>>
>>>> What the what?  I would think that should KeyError, but it runs fine.
>>>>  Someone splain.
>>>>
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>>>>
>>>
>>>
>>> --
>>> "I disapprove of what you say, but I will defend to the death your right
>>> to say it." -- Evelyn Beatrice Hall (summarizing Voltaire)
>>> "The people's good is the highest law." -- Cicero
>>>
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>>
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>>
>>
>
>
> --
> "I disapprove of what you say, but I will defend to the death your right
> to say it." -- Evelyn Beatrice Hall (summarizing Voltaire)
> "The people's good is the highest law." -- Cicero
>
> _______________________________________________
> Chicago mailing list
> Chicago at python.org
> http://mail.python.org/mailman/listinfo/chicago
>
>
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