Java LongStream average()用法及代碼示例

Java 8中的java.util.stream.LongStream處理原始Longs。它有助於解決舊問題，例如以新的方式在數組中找到最大值，在數組中找到最小值，數組中所有元素的總和以及數組中所有值的平均值。 LongStream average()返回一個OptionalDouble，描述此流的元素的算術平均值；如果此流為空，則返回一個空的Optional。
用法:

OptionalDouble average()

Where, OptionalDouble is a container object 
which may or may not contain a double value.

下麵給出一些示例，以更好地理解該函數。
示例1:

// Java code for LongStream average() 
import java.util.*; 
import java.util.stream.LongStream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // creating a stream 
        LongStream stream = LongStream.of(2L, 3L, 4L, 
                                          5L, 6L, 7L, 8L); 
  
        // OptionalDouble is a container object 
        // which may or may not contain a 
        // doouble value. 
        OptionalDouble obj = stream.average(); 
  
        // If a value is present, isPresent() will 
        // return true and getAsDouble() will 
        // return the value 
        if (obj.isPresent()) { 
            System.out.println(obj.getAsDouble()); 
        } 
        else { 
            System.out.println("-1"); 
        } 
    } 
}

輸出：

5.0

示例2:

// Implementation of LongStream average() 
import java.util.*; 
import java.util.stream.LongStream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // creating a stream 
        LongStream stream = LongStream.of(2L, 3L, 3L, 4L, 6L, 8L, 8L); 
  
        // OptionalDouble is a container object 
        // which may or may not contain a 
        // doouble value. 
        OptionalDouble obj = stream.average(); 
  
        // If a value is present, isPresent() will 
        // return true and getAsDouble() will 
        // return the value 
        if (obj.isPresent()) { 
            System.out.println(obj.getAsDouble()); 
        } 
        else { 
            System.out.println("-1"); 
        } 
    } 
}

輸出：

4.857142857142857

相關用法

注：本文由純淨天空篩選整理自Sahil_Bansall大神的英文原創作品 LongStream average() in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。