[Python-ideas] Re: Argumenting in favor of first()

Dec. 8, 2019


      
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On 8 Dec 2019, at 20:11, Guido van Rossum <guido@python.org> wrote:

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On Sun, Dec 8, 2019 at 11:03 AM Anders Hovmöller <boxed@killingar.net> wrote:
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On 8 Dec 2019, at 19:40, Guido van Rossum <guido@python.org> wrote:
def first(it, /, default=None):
    it = iter(it)
    try:
        return next(it)
    except StopIteration:
        return default
Why ban the use of keyword argument for the default value?
You must misremember PEP 570. This use of `/` means that `it` must be passed positional (it's mandatory and it's the "main" argument), but that `default` can be specified positionally or via a keyword.
Ah. Sorry. My bad.