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elm

What is the remainder operator for Elm

I have this function

result = 
  add 1 2 |> \a -> a % 2 == 0)

and I am getting this error

Elm does not use (%) as the remainder operator

When I look at the docs I see I can use modBy, so I tried this.

result =
   add 1 2 |> (\a -> a modBy 2 == 0)

But that gives me the following error.

This function cannot handle the argument sent through the (|>) pipe:
Solution

  • The % operator was removed in 0.19 to reduce the confusion between rem and mod.

    modBy and remainderBy are regular functions. You use them like:

    result = add 1 2 |> (\a -> modBy 2 a == 0)

    or, if you prefer a functional composition variant of the code:

    result = add 1 2 |> modBy 2 >> (==) 0

    As a historical note, there used to be a way to call functions infix using backticks notation:

     a `modBy` 2

    but this was removed in 0.18