On Wed, 16 Jul 2014 10:10:07 -0700, Devin Jeanpierre
wrote:
> On Wed, Jul 16, 2014 at 6:37 AM, R. David Murray
> wrote:
> > IMO, preventing someone from shooting themselves in the foot by modifying
> > something they shouldn't modify according to the API is not a Python
> > use case ("consentin
On Wed, Jul 16, 2014 at 6:37 AM, R. David Murray wrote:
> IMO, preventing someone from shooting themselves in the foot by modifying
> something they shouldn't modify according to the API is not a Python
> use case ("consenting adults").
Then why have immutable objects at all? Why do you have to p
On Wed, Jul 16, 2014 at 09:47:59AM -0400, R. David Murray wrote:
> It would be nice to be able to return a frozendict instead of having the
> overhead of building a new dict on each call.
There already is an in-between available both to Python and C:
PyDictProxy_New() / types.MappingProxyType. It
On Wed, Jul 16, 2014 at 7:47 AM, R. David Murray wrote:
> After I hit send on my previous message, I thought more about your
> example. One of the issues here is that modifying the dict breaks an
> invariant of the API. I have a similar situation in the email module,
> and I used the same soluti
On Wed, 16 Jul 2014 14:04:29 -, dw+python-...@hmmz.org wrote:
> On Wed, Jul 16, 2014 at 09:47:59AM -0400, R. David Murray wrote:
>
> > It would be nice to be able to return a frozendict instead of having the
> > overhead of building a new dict on each call.
>
> There already is an in-between
On Wed, 16 Jul 2014 03:27:23 +0100, MRAB wrote:
> >>> # Try modifying the pattern object.
> ... p.groupindex['JUNK'] = 'foobar'
> >>>
> >>> # What are the named groups now?
> ... p.groupindex
> {'first': 1, 'second': 2, 'JUNK': 'foobar'}
> >>>
> >>> # And the match object?
> ... m.groupdict()
On Wed, 16 Jul 2014 03:27:23 +0100, MRAB wrote:
> Here's another use-case.
>
> Using the 're' module:
>
> >>> import re
> >>> # Make a regex.
> ... p = re.compile(r'(?P\w+)\s+(?P\w+)')
> >>>
> >>> # What are the named groups?
> ... p.groupindex
> {'first': 1, 'second': 2}
> >>>
> >>> # Per
On 2014-07-16 00:48, Russell E. Owen wrote:
In article
,
Chris Angelico wrote:
On Mon, Jul 14, 2014 at 12:04 AM, Jason R. Coombs wrote:
> I can achieve what I need by constructing a set on the ‘items’ of the
dict.
>
set(tuple(doc.items()) for doc in res)
>
> {(('n', 1), ('err', No
In article
,
Chris Angelico wrote:
> On Mon, Jul 14, 2014 at 12:04 AM, Jason R. Coombs wrote:
> > I can achieve what I need by constructing a set on the âitemsâ of the
> > dict.
> >
> set(tuple(doc.items()) for doc in res)
> >
> > {(('n', 1), ('err', None), ('ok', 1.0))}
>
> This is
On 13 July 2014 13:43, wrote:
> In its previous form, the PEP seemed more focused on some false
> optimization capabilities of a read-only type, rather than as here, the
> far more interesting hashability properties. It might warrant a fresh
> PEP to more thoroughly investigate this angle.
RIght
On Sun, Jul 13, 2014 at 06:43:28PM +, dw+python-...@hmmz.org wrote:
> if d:
> d = d.copy()
To cope with iterables, "d = d.copy()" should have read "d = dict(d)".
David
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On Sun, Jul 13, 2014 at 02:04:17PM +, Jason R. Coombs wrote:
> PEP-416 mentions a MappingProxyType, but that’s no help.
Well, it kindof is. By combining MappingProxyType and UserDict the
desired effect can be achieved concisely:
import collections
import types
class frozendict(c
I find it handy to use named tuple as my database mapping type. It allows you
to perform this behavior seamlessly.
-Mark
> On Jul 13, 2014, at 7:04, "Jason R. Coombs" wrote:
>
> I repeatedly run into situations where a frozendict would be useful, and
> every time I do, I go searching and fin
On Mon, Jul 14, 2014 at 12:04 AM, Jason R. Coombs wrote:
> I can achieve what I need by constructing a set on the ‘items’ of the dict.
>
set(tuple(doc.items()) for doc in res)
>
> {(('n', 1), ('err', None), ('ok', 1.0))}
This is flawed; the tuple-of-tuples depends on iteration order, which
m
The PEP has been rejected, but the MappingProxyType is now public:
$ ./python
Python 3.5.0a0 (default:5af54ed3af02, Jul 12 2014, 03:13:04)
>>> d={1:2}
>>> import types
>>> d = types.MappingProxyType(d)
>>> d
mappingproxy({1: 2})
>>> d[1]
2
>>> d[1] = 3
Traceback (most recent call last):
File "",
I repeatedly run into situations where a frozendict would be useful, and every
time I do, I go searching and find the (unfortunately rejected) PEP-416. I'd
just like to share another case where having a frozendict in the stdlib would
be useful to me.
I was interacting with a database and had a
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