On Sat, Jul 29, 2017 at 6:49 AM, Nick Coghlan wrote:
> It's possible to write builtin types that are truly immutable, and
> there are several examples of that (direct instances of object, tuple
> instances, instances of the builtin numeric types),
Maybe this is an argument for namedtuple to be
On 29 July 2017 at 04:56, Mike Miller wrote:
> Nice. Ok, so there are different dimensions of mutability.
>
> Still, haven't found any "backdoors" to object(), the one I claimed was
> immutable.
It's possible to write builtin types that are truly immutable, and
there are several examples of that
Nice. Ok, so there are different dimensions of mutability.
Still, haven't found any "backdoors" to object(), the one I claimed was
immutable.
-Mike
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Yes, but A objects have no slots, no dict, do not accept attribute
assignment, but are mutable.
>>> a = A()
>>> a
[]
>>> a.__slots__
()
>>> a.__dict__
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'A' object has no attribute '__dict__'
>>> a.append(1)
>>> a.append(2)
>>
That's a subclass. Also:
>>> class A(list): __slots__ = ()
...
>>>
>>> a = A()
>>> a.foo = 'bar'
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'A' object has no attribute 'foo'
-Mike
On 2017-07-28 01:06, Antoine Rozo wrote:
> If an object has no slots or dict and
> If an object has no slots or dict and does not accept attribute
assignment, is it not effectively immutable?
No, not necessarily.
class A(list): __slots__ = ()
2017-07-28 10:00 GMT+02:00 Mike Miller :
>
>
> On 2017-07-27 18:02, Chris Angelico wrote:
> > As Ivan said, this is to do with __slot
On 2017-07-27 18:02, Chris Angelico wrote:
> As Ivan said, this is to do with __slots__. It's nothing to do with
> immutability:
>>> object().__slots__
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'object' object has no attribute '__slots__'
>>> object().__dict__
T
On Thu, Jul 27, 2017 at 05:09:56PM -0700, Mike Miller wrote:
> I've never liked that error message either:
>
> >>> object().foo = 'bar'
> Traceback (most recent call last):
> File "", line 1, in
> AttributeError: 'object' object has no attribute 'foo'
>
>
> Should say the "obj
On Fri, Jul 28, 2017 at 10:09 AM, Mike Miller wrote:
> I've never liked that error message either:
>
> >>> object().foo = 'bar'
> Traceback (most recent call last):
> File "", line 1, in
> AttributeError: 'object' object has no attribute 'foo'
>
>
> Should say the "object is imm
I've never liked that error message either:
>>> object().foo = 'bar'
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'object' object has no attribute 'foo'
Should say the "object is immutable," not writable, or something of the sort.
On 2017-07-27 09:
This error message is the same for types with __slots__, and probably it is
indeed a bit too terse.
--
Ivan
On 27 July 2017 at 18:26, Chris Barker wrote:
> Since we are talking about namedtuple and implementation, I just noticed:
>
> In [22]: Point = namedtuple('Point', ['x', 'y'])
> In [23]:
Since we are talking about namedtuple and implementation, I just noticed:
In [22]: Point = namedtuple('Point', ['x', 'y'])
In [23]: p = Point(2,3)
In [24]: p.x = 5
---
AttributeErrorTraceback (most
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