Java Java.util.function.DoublePredicate用法及代碼示例

DoublePredicate接口被引入JDK 8。該接口封裝在java.util.function包。它對 Double 對象進行操作並根據條件返回謂詞值。它是一個函數接口因此可以用於拉姆達表達式還。

public interface DoublePredicate

方法

test()：此函數對雙精度值進行條件檢查，並返回一個表示結果的布爾值。

boolean test(double value)

and()：該函數對當前對象和作為參數接收的對象進行 AND 運算，並返回新形成的謂詞。該方法有一個默認實現。

default DoublePredicate and(DoublePredicate other)

negate()：該函數返回當前謂詞的逆，即反轉測試條件。該方法有一個默認實現。

default DoublePredicate negate()

or()：該函數對當前對象和作為參數接收的對象進行 OR 運算，並返回新形成的謂詞。該方法有一個默認實現。

default DoublePredicate or(DoublePredicate other)

例子：

Java


// Java example to demonstrate DoublePredicate interface
import java.util.function.DoublePredicate;
public class DoublePredicateDemo {
    public static void main(String[] args)
    {
        // DoublePredicate to check square
        // of x is less than 100
        DoublePredicate db
            = (x) -> { return x * x < 100.0; };
        System.out.println("100 is less than 100 "
                           + db.test(10));
        DoublePredicate db3;
        // Test condition reversed
        db.negate();
        System.out.println("100 is greater than 100 "
                           + db.test(10));
        DoublePredicate db2 = (x) ->
        {
            double y = x * x;
            return y >= 36 && y < 1000;
        };
        // Test condition ANDed
        // with another predicate
        db3 = db.and(db2);
        System.out.println("81 is less than 100 "
                           + db3.test(9));
        db3 = db.or(db2);
        // Test condition ORed with another predicate
        System.out.println("49 is greater than 36"
                           + " and less than 100 "
                           + db3.test(7));
    }
}

輸出：

100 is less than 100 false
100 is greater than 100 false
81 is less than 100 true
49 is greater than 36 and less than 100 true

參考： https://docs.oracle.com/javase/8/docs/api/java/util/function/DoublePredicate.html

相關用法

注：本文由純淨天空篩選整理自CharchitKapoor大神的英文原創作品 Java.util.function.DoublePredicate interface 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。