[IPython-dev] display of dicts?

[Chris Barker]

Thanks Nathan,

And to confirm, this is the stdlib's pprint module, yes?

(which does seem to show the same behavior)

-CHB



On Mon, Dec 18, 2017 at 5:40 PM, Nathan Goldbaum <nathan12343 at gmail.com>
wrote:

> IPython does use pretty-printing by default. You can control it with the
> %pprint magic, in your IPython configuration, with the
> PlainTextFormatter.pprint option, or with the --pprint command line
> argument when starting IPython.
>
> http://ipython.readthedocs.io/en/stable/config/options/
> terminal.html#configtrait-PlainTextFormatter.pprint
>
>
>
> On Mon, Dec 18, 2017 at 7:08 PM, Chris Barker <chris.barker at noaa.gov>
> wrote:
>
>> As Guido has just declared that dicts will now officially preserve order:
>>
>> https://mail.python.org/pipermail/python-dev/2017-December/151283.html
>>
>> I was playing around  them in py3.6 ipython, and found some (to me) odd
>> behavior:
>>
>> In [1]: d = {'one':1, 'two':2, 'three':3}
>>
>> In [2]: d
>> Out[2]: {'one': 1, 'three': 3, 'two': 2}
>>
>> Hmm -- order does not appear to be preserved.
>>
>> But then:
>>
>> In [3]: str(d)
>> Out[3]: "{'one': 1, 'two': 2, 'three': 3}"
>>
>> In [4]: repr(d)
>> Out[4]: "{'one': 1, 'two': 2, 'three': 3}"
>>
>> In [5]: d.values()
>> Out[5]: dict_values([1, 2, 3])
>>
>> In [6]: d.keys()
>> Out[6]: dict_keys(['one', 'two', 'three'])
>>
>> In [7]: d.items()
>> Out[7]: dict_items([('one', 1), ('two', 2), ('three', 3)])
>>
>> Order IS preserved.
>>
>> So presumably iPython is calling sorted() or some such when displaying a
>> dict.
>>
>> Is that that case? Is that documented anywhere?? I can't find it.
>>
>> And with Python >= 3.6, dict order is preserved, so it would probably be
>> better to NOT mess with dict order when displaying them in iPython.
>>
>> SIDE NOTE:
>>
>> I had a bit of trouble finding this mailing list -- google still points
>> to the old ones on scipy.org. -- maybe we can put a note on the home
>> page of those lists that they are been moved??
>>
>> (I only noticed, 'cause the archives of those stop last March)
>>
>> -Chris
>>
>>
>>
>>
>>
>> --
>>
>> Christopher Barker, Ph.D.
>> Oceanographer
>>
>> Emergency Response Division
>> NOAA/NOS/OR&R            (206) 526-6959   voice
>> 7600 Sand Point Way NE   (206) 526-6329   fax
>> Seattle, WA  98115       (206) 526-6317   main reception
>>
>> Chris.Barker at noaa.gov
>>
>> _______________________________________________
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>> IPython-dev at python.org
>> https://mail.python.org/mailman/listinfo/ipython-dev
>>
>>
>
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>


-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chris.Barker at noaa.gov
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