Scala Iterator count() 方法与示例

count()方法属于Abstract Iterator类的具体值成员。它在类IterableOnceOps中定义。它计算所述集合中满足给定谓词的元素的数量。

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

Where, p is the predicate used.

Return Type :It returns the number of elements satisfying the predicate p.

示例 #1：

// Scala program of count()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating an Iterator 
        val iter = Iterator(5, 6, 8)
          
        // Applying count method
        val result = iter.count(x => {x % 3 != 0})
          
        // Displays output
        println(result)
      
    }
}

输出：

2

在这里，只有两个元素满足所述谓词，因此返回两个。
示例 #2：

// Scala program of count()
// method
  
// Creating object
object GfG
{ 
  
    // Main method
    def main(args:Array[String])
    {
      
        // Creating an Iterator 
        val iter = Iterator(4, 6, 10, 11, 13)
          
        // Applying count method
        val result = iter.count(x => {x % 2 == 0})
          
        // Displays output
        println(result)
      
    }
}

输出：

3