display of dicts?

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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

[email protected]

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<div dir=3D"ltr"><div>As Guido has just declared that dicts will now offici=
ally preserve order:<br clear=3D"all"><div><br><a href=3D"https://mail.pyth=
on.org/pipermail/python-dev/2017-December/151283.html">https://mail.python.=
org/pipermail/python-dev/2017-December/151283.html</a><br><br></div><div>I =
was playing around=C2=A0 them in py3.6 ipython, and found some (to me) odd =
behavior:<br><br><span style=3D"font-family:monospace,monospace">In [1]: d =
=3D {&#39;one&#39;:1, &#39;two&#39;:2, &#39;three&#39;:3}<br><br>In [2]: d<=
br>Out[2]: {&#39;one&#39;: 1, &#39;three&#39;: 3, &#39;two&#39;: 2}<br><br>=
</span></div>Hmm -- order does not appear to be preserved.<br><br></div>But=
 then:<span style=3D"font-family:monospace,monospace"></span><br><div><span=
 style=3D"font-family:monospace,monospace"></span><div><span style=3D"font-=
family:monospace,monospace"><br>In [3]: str(d)<br>Out[3]: &quot;{&#39;one&#=
39;: 1, &#39;two&#39;: 2, &#39;three&#39;: 3}&quot;<br><br>In [4]: repr(d)<=
br>Out[4]: &quot;{&#39;one&#39;: 1, &#39;two&#39;: 2, &#39;three&#39;: 3}&q=
uot;<br><br>In [5]: d.values()<br>Out[5]: dict_values([1, 2, 3])<br><br>In =
[6]: d.keys()<br>Out[6]: dict_keys([&#39;one&#39;, &#39;two&#39;, &#39;thre=
e&#39;])<br><br>In [7]: d.items()<br>Out[7]: dict_items([(&#39;one&#39;, 1)=
, (&#39;two&#39;, 2), (&#39;three&#39;, 3)])<br></span><br></div><div>Order=
 IS preserved.<br><br></div><div>So presumably iPython is calling sorted() =
or some such when displaying a dict. <br><br></div><div>Is that that case? =
Is that documented anywhere?? I can&#39;t find it.<br><br></div><div>And wi=
th Python &gt;=3D 3.6, dict order is preserved, so it would probably be bet=
ter to NOT mess with dict order when displaying them in iPython.<br><br></d=
iv><div>SIDE NOTE:<br></div><div><br>I had a bit of trouble finding this ma=
iling list -- google still points to the old ones on <a href=3D"http://scip=
y.org">scipy.org</a>. -- maybe we can put a note on the home page of those =
lists that they are been moved??<br><br></div><div>(I only noticed, &#39;ca=
use the archives of those stop last March)<br><br></div><div>-Chris<br></di=
v><div><br></div><div><br></div><div><br><br></div><div><br>-- <br><div cla=
ss=3D"gmail_signature"><br>Christopher Barker, Ph.D.<br>Oceanographer<br><b=
r>Emergency Response Division<br>NOAA/NOS/OR&amp;R =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0(206) 526-6959=C2=A0=C2=A0 voice<br>7600 Sand Point Way NE=
 =C2=A0=C2=A0(206) 526-6329=C2=A0=C2=A0 fax<br>Seattle, WA =C2=A098115 =C2=
=A0 =C2=A0 =C2=A0=C2=A0(206) 526-6317=C2=A0=C2=A0 main reception<br><br><a =
href=3D"mailto:[email protected]" target=3D"_blank">[email protected]=
ov</a></div>
</div></div></div>

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