Scala Map remove() 方法与示例

remove()方法用于从映射中删除键并仅返回其值。

Method Definition: def remove(key: A): Option[B]

Return Type: It returns the value of the key present in the above method as argument.

示例 #1：

// Scala program of remove()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating map
        val m1 = scala.collection.mutable.Map("geeks" -> 5, 
                                    "for" -> 3, "cs" -> 2)
          
        // Applying remove method
        val result = m1.remove("for")
          
        // Displays output
        println(result)
      
    }
}

输出：

Some(3)

我们在这里使用可变映射，因为remove方法是可变映射的成员。
示例 #2：

// Scala program of remove()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating map
        val m1 = scala.collection.immutable.Map("geeks" -> 5, 
                                        "for" -> 3, "cs" -> 2)
          
        // Applying remove method
        val result = m1.remove("for")
          
        // Displays output
        println(result)
      
    }
}

输出：

prog.scala:16: error: value remove is not a member of scala.collection.immutable.Map[String, Int]
val result = m1.remove(“for”)
^
one error found

因此，如果我们使用不可变映射，则会出现编译时错误。