Question

I want to write a short functional sum-function for a List of BigDecimal and tried with:

def sum(xs: List[BigDecimal]): BigDecimal = (0 /: xs) (_ + _)

But I got this error message:

<console>:7: error: overloaded method value + with alternatives:
  (x: Int)Int <and>
  (x: Char)Int <and>
  (x: Short)Int <and>
  (x: Byte)Int
 cannot be applied to (BigDecimal)
       def sum(xs: List[BigDecimal]): BigDecimal = (0 /: xs) (_ + _)
                                                                ^

If I use Int instead, that function works. I guess this is because BigDecimal’s operator overloading of +. What is a good workaround for BigDecimal?

Answer 1

The problem is in inital value. The solution is here and is quite simple:

 sum(xs: List[BigDecimal]): BigDecimal = (BigDecimal(0) /: xs) (_ + _)