vfsoraki
Enum.reduce/2 throws Enum.EmptyError
Example:
iex(1)> Enum.reduce([], fn x,y -> y end)
** (Enum.EmptyError) empty error
(elixir) lib/enum.ex:1754: Enum.reduce/2
I see nothing in docs about not being able to reduce an empty list.
I felt like this should return back [], but seems not.
Note that Enum.reduce/3 works fine, but I need Enum.reduce/2.
Am I doing it wrong?
PS. This is Elixir 1.5.1
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ericmj
Enum.reduce/3 works because it will just return the accumulator in the second argument. With Enum.reduce/2 the first element in the enumerable is used as the initial accumulator but if the enumerable is empty then what should be returned.
We can’t return [] because that does not make sense in many applications, for example if you want to sum a list:
Enum.reduce([1, 2, 3, 4], fn(x, acc) -> x * acc end) #=> 10
Enum.reduce([], fn(x, acc) -> x * acc end) #=> [] / 0 ???
Why do you specifically need Enum.reduce/2?
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