scala「刪除」不起作用

Question

根據「Scala編程」一書的第44頁，list數據結構中存在remove函數。但是，當我在解釋器中嘗試示例時，我不斷收到錯誤。有誰知道爲什麼？下面是一個示例

scala> val x = List(1,2,3,4,5,6,7,8,9) 
x: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8, 9) 

scala> x.remove(_ < 5) 
<console>:9: error: value remove is not a member of List[Int] 
       x.remove(_ < 5) 
       ^

scala> x.remove(s => s == 5) 
<console>:9: error: value remove is not a member of List[Int] 
       x.remove(s => s == 5) 
       ^

scala> val y = List("apple","Oranges","pine","sol") 
y: List[String] = List(apple, Oranges, pine, sol) 

scala> y.remove(s => s.length ==4) 
<console>:9: error: value remove is not a member of List[String] 
       y.remove(s => s.length ==4) 

Answer 1

List在早期版本中有一個刪除方法，但它已在2.8中棄用並在2.9中刪除。改爲使用filterNot。

Answer 2

ListBuffer具有remove方法，但不是List。請參閱here for info on how to idiomatically remove from an immutable List（很明顯會創建一個新列表！）