On Tue, Oct 31, 2017 at 07:51:02AM +1100, Cameron Simpson wrote:
> return the(nodes)
>
> It's this kind of thing that expresses my intent better than the:
>
> node, = nodes
> return node
>
> idiom.
If the intent is to indicate that there is only one node, then
"the(nodes)" fails completely. "The" can refer to plurals as easily as
singular:
"Wash the dirty clothes."
(Later) "Why did you only wash one sock?"
The simplest implementation of this "single()" function I can think of
would be:
def single(iterable):
result, = iterable
return result
That raises ValueError if iterable has too few or too many items, which
I believe is the right exception to use. Conceptually, there's no
indexing involved, so IndexError would be the wrong exception to use.
We're expecting a compound value (an iterable) with exactly one item. If
there's not exactly one item, that's a ValueError.
--
Steve
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