George Sakkis a écrit :
> bruno de chez modulix en face wrote:
>
>
>>>and there's no compelling reason for dict(**kwds).
>>
>>Yes there is : this *is* the ordinary Python syntax - calling a type to
>>get an instance of it. The dict-litteral syntax is mostly syntactic
>>sugar.
>
>
> The thing is there are four (at least?) ways to get a dict instance:
>
> In [1]: d1={'name':'mike', 'age':23}
>
> In [2]: d2=dict(d1)
>
> In [3]: d3=dict(**d1)
>
> In [4]: d4=dict(d1.items())
>
> In [5]: d1==d2==d3==d4
> Out[5]: True
>
> Talk about "there should be one and preferably one obvious way to do
> it".
>
This actually makes 2 (two) ways of creating a dict:
- the default call to type (ie : dict(...)
- the syntactic sugar dict-litteral syntax.
The fact that dict() takes either a sequence of pairs and/or keyword
args (yes, you can use both at once) doesn't make for 2 distinct ways.
And the second syntax (litteral) is nothing else than syntaxic sugar -
read : a special case. So if we are to get rid of one or the other, it's
the dict-litteral syntax that should go away.
>
>>>Perhaps it's something that should be reconsidered for Py3K
>>
>>Hopefully not. The fact that you fail to understand why a given feature
>>exists and how it can be useful is not a reason to ask for arbitrary
>>restrictions on the language.
>
>
> Perhaps you fail to understand that the given feature is
> 1) redundant (see above).
see above for an answer on this. FWIW, there are a *lot* of other
syntactic-sugar redundancy in Python. Most of which you're probably not
even aware of.
> 2) restricting in a more serious sense: the future addition of optional
> keyword arguments that affect the dict's behaviour.
This has already been discussed, and IIRC no-one managed to make a
*serious* point about it. The actual signature of dict() is perfectly
sensible for 99% of uses case, and I *never* had a need for "keyword
arguments that affect the dict's behaviour" in 6+ years of Python
programming.
If you want another behaviour, feel free to subclass dict or implement
your own dict-like - FWIW, that's what I do when the need arises.
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