scala过滤元组列表的列表

Question

I have a list of lists with tuples (char, Int) like

val raw = List(List((a,0), (b,0)), List((a,1), (b,0)), List((a,2), (b,0)), List((a,0), (b,1)), List((a,1), (b,1)), List((a,2), (b,1)), List((a,0), (b,2)), List((a,1), (b,2)), List((a,2), (b,2)))`

I want to filter out all tuples with where the Int is 0. So the result should be:

List(List(), List((a,1)), List((a,2)), List((b,1)), List((a,1), (b,1)), List((a,2), (b,1)), List((b,2)), List((a,1), (b,2)), List((a,2), (b,2)))

I tried to do a map and then a filter but the compiler complains with incompatible types: ((Int, Char) => Boolean expected but found ((Int, Char) => Unit)

raw.map(_.filter(tuple => match {
  (_,0) => false
  (_,_) => true
})

Were do I go wrong

Answer 1

这是正确的：

raw.map(_.filter(_._2 != 0))

Answer 2

This is close to what you tried:

raw.map(_.filter({
  case (_,0) => false
  case (_,_) => true
}))