Le 19/07/2018 à 10:36, Chris Angelico a écrit :
On Thu, Jul 19, 2018 at 5:45 PM, Brice Parent <cont...@brice.xyz> wrote:
The biggest drawback of this, is that (if I understand it well), it may be
done quite easily without any change to the language:
def first_set(*elements): # please don't mind the name of the function,
it's not the purpose here
""" Will return the first element that is not None """
for element in elements:
if element is not None:
return element
raise AllNoneException()
first_set(3, 5) # -> 3
first_set(None, 5) # -> 5
first_set(None, None, 8, 10) # -> 8
first_set(None, Car(model="sport")).buy() # calling
Car(model="sport").buy()
first_set(None, ["a", "b", "c"])[1] # -> "b"
first_set(None, None) # -> exception is raised
(note that such function could even accept a "rejected_values" kwarg, like
`rejected_values=(None, [], "")`, just by replacing the `if` clause by `if
element not in rejected_values:`)
No it can't, for the same reason that the 'and' and 'or' operators
can't be implemented cleanly as functions: it short-circuits. The
right-hand operator _will not_ be evaluated unless the left is None.
ChrisA
Thanks for the clarification, I didn't think about that.
It doesn't make it beautiful or easily readable, but at least, I
understand how it may be useful then!
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