下面類在該行val userList : List[User]
拋出一個編譯器錯誤:Scala編譯器錯誤:只有類可以有聲明,但未定義的成員
Multiple markers at this line
- only classes can have declared but undefined members
- only classes can have declared but undefined members
這裏是整個代碼:
class SimilarityData {
case class User(id: String, jCoeff : Int)
def getUsers() =
{
val userList : List[User]
userList :+ new User("1" , 1);
}
}
是什麼原因造成錯誤?
爲什麼我不能使用'val userList:List [User] = _'? –
@ user470184試一試...試驗&學習! –
我應該澄清:+不會修改現有列表,它會創建一個新列表並將其返回。 –