Scala Map count() 方法与示例

count()方法用于计算 Map 中的键对。

Method Definition: def count(p: ((A, B)) => Boolean): Int

Return Type: It returns the number of keys present in the map that satisfies the given predicate.

示例 #1：

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

输出：

3

示例 #2：

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

输出：

2

因此，相同的键只计算一次。