CODEWITHSUNDEEP
enumselixirphoenix-framework
Bitwise
Bitwise

Reputation: 8461

no function clause matching in Enum.reduce/3

I'm getting this error when trying to sum a list I'm getting back from a comprehension: 

range = 1..999

multiple_of_3_or_5? = fn(n) -> (rem(n, 3) == 0 || rem(n, 5) == 0) end
IO.inspect for n <- range, multiple_of_3_or_5?.(n),
  do: Enum.reduce n, 0, fn(x) -> x end

#=> ** (FunctionClauseError) no function clause matching in Enum.reduce/3

Why am I getting this error?

Upvotes: 0

Views: 1251

Answers (2)

Tuyen Cao
Tuyen Cao

Reputation: 1081

The first and third param are wrong. You can try this

range = 1..999
multiple_of_3_or_5? = fn(n) -> (rem(n, 3) == 0 || rem(n, 5) == 0) end
for n <- range, multiple_of_3_or_5?.(n) do n end |> Enum.reduce(0, 
fn(x, acc) -> x + acc end)

or

range = 1..999
multiple_of_3_or_5? = fn(n) -> (rem(n, 3) == 0 || rem(n, 5) == 0) end
Enum.reduce_while(range, 0, fn i, acc ->
  if multiple_of_3_or_5?.(i), do: {:cont, acc + i}, else: {:cont, acc}
end)

Upvotes: 0

גלעד ברקן
גלעד ברקן

Reputation: 23955

The function in the third parameter of Enum.reduce needs to have two parameters, the element from the enumerable and an accumulator. You currently only have one parameter, x.

Upvotes: 1

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