Scala Map exists() 方法与示例

exists()方法用于检查给定谓词是否满足映射的元素。

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

Return Type: It returns true if the stated predicate holds true for some elements of the map else it returns false.

示例 #1：

// Scala program of exists()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating map
        val m1 = Map("geeks" -> 5, "for" -> 3)
          
        // Applying exists method
        val result = m1.exists(x => x._1 == "for" && x._2 == 3)
          
        // Displays output
        println(result)
      
    }
}

输出：

true

因此，此处所述谓词对于第二个键值对为 true，因此返回 true。
示例 #2：

// Scala program of exists()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating map
        val m1 = Map("geeks" -> 5, "for" -> 3)
          
        // Applying exists method
        val result = m1.exists(x => x._1 == "geeks" && x._2 == 3)
          
        // Displays output
        println(result)
      
    }
}

输出：

false