Java DoubleStream filter()示例

DoubleStream filter(DoublePredicate predicate) 返回一个由这个流中符合给定谓词的元素组成的流。这是一个 中间操作。 这些操作总是懒惰的，即执行中间操作如filter()实际上并不执行任何过滤，而是创建一个新的流，当遍历时，包含初始流中符合给定谓词的元素。

语法:

DoubleStream filter(DoublePredicate predicate)

参数

DoubleStream : 一个原始双值元素的序列。
DoublePredicate : 一个双值参数的谓词（布尔值函数）。

返回值： 该函数返回新的流。

例1： DoubleStream的filter()方法。

// Java code for DoubleStream filter
// (DoublePredicate predicate) to get a stream
// consisting of the elements of this
// stream that match the given predicate.
import java.util.*;
import java.util.stream.DoubleStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating an DoubleStream
        DoubleStream stream = DoubleStream.of(3.6, 5.4, 6.6, 8.1, 9.7);
  
        // Using DoubleStream filter(DoublePredicate predicate)
        // to get a stream consisting of the
        // elements that are greater than 5.7
        stream.filter(num -> num > 5.7)
            .forEach(System.out::println);
    }
}

输出:

6.6
8.1
9.7

例2： DoubleStream的filter()方法。

// Java code for DoubleStream filter
// (DoublePredicate predicate) to get a stream
// consisting of the elements of this
// stream that match the given predicate.
import java.util.*;
import java.util.stream.DoubleStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating an DoubleStream
        DoubleStream stream = DoubleStream.of(3.6, 5.4, 6.6, 8.1, 9.7);
  
        // Using DoubleStream filter(DoublePredicate 
        // predicate) to get a stream consisting of 
        // the elements that when divided by 2
        // gives quotient > 2.3
        stream.filter(num -> num / 2.0 > 2.3)
            .forEach(System.out::println);
    }
}