如何在地圖基礎上階

Question

的條件替換值的關鍵，我有幾個不可變的映射記錄，如：

val map = Map("number"->7,"name"->"Jane","city"->"New York") 

我需要確定"name"鍵爲每個記錄，並檢查其值。如果值是​​3210，我需要用"Doe"替換並更新地圖記錄。

Answer 1

這可以通過簡單的映射操作和模式匹配來實現。

scala> val dictionary = Map("number"->7,"name"->"Jane","city"->"New York") 
map: scala.collection.immutable.Map[String,Any] = Map(number -> 7, name -> Jane, city -> New York) 

scala> dictionary map { 
    | case ("name","Jane") => "name" -> "Doe" 
    | case x => x 
    | } 
res3: scala.collection.immutable.Map[String,Any] = Map(number -> 7, name -> Doe, city -> New York) 

Answer 2

一個簡單if else邏輯應該做的伎倆

map.map(k => { 
    if(k._1.toString.equalsIgnoreCase("name") && k._2.toString.equalsIgnoreCase("jane")) 
    (k._1, "Doe") 
    else 
    k 
}) 

或簡單match case應該做的伎倆以及由@流氓一個

map.map(k => (k._1.toString, k._2.toString) match{ 
    case ("name", "Jane") => k._1 -> "Doe" 
    case _ => k 
}) 

感謝解釋