Scala sum Map 值

在 Scala 中，地图元素的总和可以通过使用foldLeft方法来完成。

Syntax : m1.foldLeft(0)(_+_._1)

Here, m1 is used for a Map, foldLeft is a method that takes an initial value zero. it will take previous result and add it to the next map key value.

Return Type: It returns the sum of all the elements of the map.

示例 #1：

// Scala program of sum()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating a map
        val m1 = Map(3 -> "geeks", 1 -> "for", 2 -> "cs")
          
        // Applying sum method
        val result = m1.foldLeft(0)(_+_._1)
          
        // Displays output
        println(result)
      
    }
}

输出：

6

这里， foldLeft方法中的零是初始值。
示例 #2：

// Scala program of sum()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating a map
        val m1 = Map(3 -> "geeks", 1 -> "for", 1 -> "for")
          
        // Applying sum method
        val result = m1.foldLeft(0)(_+_._1)
          
        // Displays output
        println(result)
      
    }
}

输出：

4