有人能帮我定义这个函数吗:
def lift[A, B, T](op: (T,T) => T)(f: A => T, g: B => T): (A,B) => T = /* ... */
有人能帮我定义这个函数吗:
def lift[A, B, T](op: (T,T) => T)(f: A => T, g: B => T): (A,B) => T = /* ... */
def lift[A, B, T](op: (T,T) => T)(f: A => T, g: B => T): (A,B) => T =
(a: A, b: B) => op(f(a), g(b))
这提供了
def op(a: Int, b: Int): Int = a + b
def f(x: String): Int = x.toInt
def g(x: List[String]): Int = x.length
lift(op)(f,g)("41", List("2"))
// Int = 42