[Python-3000] PEP 3132: Extended Iterable Unpacking
Christian Heimes
lists at cheimes.de
Wed May 2 02:32:35 CEST 2007
Neville Grech Neville Grech wrote:
> This reminds me a lot of haskell/prolog's head/tail list splitting. Looks
> like a good feature.
Agreed!
> a*=range(5)
> hmmn maybe in such a case, whenever there is the * operator, the resulting
> item is always a list/tuple, like the following:
> a=[[0,1,2,3,4]] ?
Did you mean *a = range(5)?
The result is too surprising for me. I would suspect that *a = range(5)
has the same output as a = range(5).
>>> *b = (1, 2, 3)
>>> b
(1, 2, 3)
>>> a, *b = (1, 2, 3)
>>> a, b
1, (2, 3)
>>> *b, c = (1, 2, 3)
>>> b, c
(1, 2), 3
>>> a, *b, c = (1, 2, 3)
>>> a, b, c
1, (2,), 3
But what would happen when the right side is too small?
>>> a, *b, c = (1, 2)
>>> a, b, c
1, (), 2
or should it raise an unpack exception?
This should definitely raise an exception
>>> a, *b, c, d = (1, 2)
Christian
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