Why not a, b += i, j? (augmented assignment via tuple unpacking)

[Steven Rumbalski]

Grant Edwards wrote:

> In article <KbRE9.534$RQ3.26615908 at newssvr17.news.prodigy.com>, Steven
> Rumbalski wrote:
> 
>> In python I can write:
>> 
>> a, b = i, j
>> 
>> but the following is not legal:
>> 
>> a, b += i, j
>> 
>> Is there a reason that allowing this would be bad?
> 
> If it were allowed, what do you propose it would do?
> 
>> Why does Python forbid this?
> 
> First tell us what you think it would do were it legal.  :)
> 

I was imagining it working like

>>> a += i
>>> b += j

I suppose it could appear that I meant

>>> a, b = (a, b) + (i, J)

The first is intuitive to me because of how the following behaves

>>> a, b = i, j

but I guess it's not intuitive to others.

By the way, I did not ask the above question because I thought that Python 
was wrong, but because I want to understand the language better.


Steven Rumbalski