Scala parameterized methods and arithmetic operations

Question

I am trying to get a simple piece of functionality to work where I have a List of Lists and I want to do some mathematical operations on the data (-, + , *, /). I want the method to take any of the following types (Int, Float, Double).

here is what I have tried:

def doSomething[T](data: List[T]){
 data reduceLeft(_ / _)
}

the following is displayed: value / is not a member of type parameter T.

How do I get this to work for the AnyVal types (Double, Int, Float)?

Update I tried implementing the suggestion in the following code:

def dot[T](l: List[List[T]])(implicit num: Numeric[T]) = 
{

    for (row <- data)
        yield for(col <- l)
            yield row zip col map {a => num.times(a._1 , a._2)}   reduceLeft (_+_)

and get the error: type mismatch; found : a._1.type (with underlying type T) required: T

Is there any way to get around that?

Answer 1

For division:

def foo[T](l: List[T])(implicit num: Numeric[T]) = num match{
     case i: Integral[_] => l reduceLeft (i.quot(_, _))
     case fr: Fractional[_] => l reduceLeft (fr.div(_, _))}

For +, - and * it's easier (plus, minus, times respectively):

def foo[T](l: List[T])(implicit num: Numeric[T]) = l reduceLeft (num.plus(_, _))