小编Ole*_*ako的帖子

如何在不创建任何新集合的情况下做到这一点 有比这更好的东西吗？

val m = scala.collection.mutable.Map[String, Long]("1" -> 1, "2" -> 2, "3" -> 3, "4" -> 4)
m.foreach(t => if (t._2 % 2 == 0) m.remove(t._1))
println(m)

PS中的Scala 2.8

有没有办法使这项工作(Scala 2.8.1):

class A
class B
def f(implicit b: B) {}
implicit val a = new A
implicit def aToB(a: A) = new B
f(a) // works ok
f // error: could not find implicit value for parameter b: B

其实我的问题是与Lift的(2.2)的依赖注入,我试图给供应商[T]转换为T和隐含需要它在类的构造函数,而不每一VAL之后增加进口:

object DependencyFactory extends Factory {
  implicit def vendorToVal[T](vendor: Vendor[T]): T = vendor.vend

  implicit val db = new FactoryMaker[DbAccess](Model) {}
  //uncommenting the following line makes it work, but can we avoid it? 
  //import db._
  implicit val userStore = new FactoryMaker[UserStore](new …