+
−
val f = (x:(Int, Int)) => if (x._1 > 3) Some(List(x)) else None+
−
+
−
assert(first(List((1,0),(2,0),(3,0),(4,0)), f) == Some(List((4,0))))+
−
assert(first(List((1,0),(2,0),(3,0)), f) == None)+
−