why del is not a function or method?

[Oren Ben-Kiki]

True... technically, "Deletion of a name removes the binding of that name
from the local or global namespace". Using `x.del()` can't do that.

That said, I would hazard to guess that `del x` is pretty rare (I have
never felt the need for it myself). Ruby doesn't even have an equivalent
operation, and doesn't seem to suffer as a result. If Python used methods
instead of global functions for `len` and `del`, and provided a
`delete_local_variable('x')` for these rare cases, that could have been a
viable solution.

So I still think it was a matter of preference rather than a pure technical
consideration. But that's all second-guessing, anyway. You'd have to ask
Guido what his reasoning was...


On Mon, Oct 16, 2017 at 7:36 PM, Ned Batchelder <ned at nedbatchelder.com>
wrote:

> On 10/16/17 12:16 PM, Oren Ben-Kiki wrote:
>
>> That doesn't explain why `del` isn't a method though. Intuitively,
>> `my_dict.delete(some_key)` makes sense as a method. Of course, you could
>> also make the same case for `len` being a method... and personally I think
>> it would have been cleaner that way in both cases. But it is a minor
>> issue,
>> if at all.
>>
>> I guess the answer is a combination of "historical reasons" and "Guido's
>> preferences"?
>>
>
> It would still need to be a statement to allow for:
>
>     del x
>
> since "x.del()" wouldn't affect the name x, it would affect the value x
> refers to.
>
> --Ned.
>
>
>>
>> On Mon, Oct 16, 2017 at 6:58 PM, Stefan Ram <ram at zedat.fu-berlin.de>
>> wrote:
>>
>> Xue Feng <xf.lotus at yahoo.com> writes:
>>>
>>>> I wonder why 'del' is not a function or method.
>>>>
>>>    Assume,
>>>
>>> x = 2.
>>>
>>>    When a function »f« is called with the argument »x«,
>>>    this is written as
>>>
>>> f( x )
>>>
>>>    . The function never gets to see the name »x«, just
>>>    its boundee (value) »2«. So, it cannot delete the
>>>    name »x«.
>>>
>>>    Also, the function has no access to the scope of »x«,
>>>    and even more so, it cannot make any changes in it.
>>>
>>>    Therefore, even a call such as
>>>
>>> f( 'x' )
>>>
>>>    will not help much.
>>>
>>> --
>>> https://mail.python.org/mailman/listinfo/python-list
>>>
>>>
> --
> https://mail.python.org/mailman/listinfo/python-list
>