Java中的 LongStream filter() 示例

LongStream filter(LongPredicate predicate)返回一个流，该流由该流中与给定谓词匹配的元素组成。这是一个中间操作。这些操作总是惰性的，即执行诸如 filter() 之类的中间操作实际上并不执行任何过滤，而是创建一个新流，当遍历该流时，它包含与给定谓词匹配的初始流的元素。

句法 ：

LongStream filter(LongPredicate predicate)

Where, LongStream is a sequence of primitive long-valued elements.
LongPredicate represents a predicate (boolean-valued function) 
of one long-valued argument and the function returns the new stream.

示例 1： LongStream 上的 filter() 方法。

// Java code for LongStream filter
// (LongPredicate predicate) to get a stream
// consisting of the elements of this
// stream that match the given predicate.
import java.util.*;
import java.util.stream.LongStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating an LongStream
        LongStream stream = LongStream.of(3L, 5L, 6L, 8L, 9L);
  
        // Using LongStream filter(LongPredicate predicate)
        // to get a stream consisting of the
        // elements that gives remainder 2 when
        // divided by 3
        stream.filter(num -> num % 3 == 2)
            .forEach(System.out::println);
    }
}

输出 ：

5
8

示例 2： LongStream 上的 filter() 方法。

// Java code for LongStream filter
// (LongPredicate predicate) to get a stream
// consisting of the elements of this
// stream that match the given predicate.
import java.util.*;
import java.util.stream.LongStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating an LongStream
        LongStream stream = LongStream.of(-2L, -1L, 0L, 1L, 2L);
  
        // Using LongStream filter(LongPredicate predicate)
        // to get a stream consisting of the
        // elements that are greater than 0
        stream.filter(num -> num > 0)
            .forEach(System.out::println);
    }
}

输出 ：

1
2