[Python-Dev] Extending tuple unpacking (original) (raw)

Greg Ewing greg.ewing at canterbury.ac.nz
Wed Oct 12 04:16:16 CEST 2005

Nick Coghlan wrote:

I'm also trying to figure out why you would ever write: [a, b, c, d] = seq

I think the ability to use square brackets is a holdover from some ancient Python version where you had to match the type of the thing being unpacked with the appropriate syntax on the lhs. It was a silly requirement from the beginning, and it became unworkable as soon as things other than lists and tuples could be unpacked.

In Py3k I expect that [...] for unpacking will no longer be allowed.

Indeed. It's a (minor) pain that optional flag variables and variable length argument lists are currently mutually exclusive. Although, if you had that rule, I'd want to be able to write:

def f(a, b, *, foo=1, bar=2): pass

Yes, I agree.

-- Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg.ewing at canterbury.ac.nz +--------------------------------------+

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