Java 中的 LongStream max()，示例
原文:https://www.geeksforgeeks.org/longstream-max-java-examples/
Java 8 中的 java.util.stream.LongStream 处理原语 longs。它以一种新的方式帮助解决了求数组中最大值、求数组中最小值、求数组中所有元素的和、求数组中所有值的平均值等问题。 LongStream max() 返回一个描述该流的最大值元素的可选值，如果该流为空，则返回一个空的可选值。
语法:
OptionalLong() max()
Where, OptionalLong is a container object which
may or may not contain a long value.
例 1 :
// Java code for LongStream max()
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(-9L, -18L, 54L,
8L, 7L, 14L, 3L);
// OptionalLong is a container object
// which may or may not contain a
// long value.
OptionalLong obj = stream.max();
// If a value is present, isPresent() will
// return true and getAsLong() will
// return the value
if (obj.isPresent()) {
System.out.println(obj.getAsLong());
}
else {
System.out.println("-1");
}
}
}
输出:
54
例 2 :
// Java code for LongStream max()
// to get the maximum value in range
// excluding the last element
import java.util.*;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// To find maximum in given range
LongStream stream = LongStream.range(50L, 75L);
// storing the maximum value in variable
// if it is present, else show -1.
long maximum = stream.max().orElse(-1);
// displaying the maximum value
System.out.println(maximum);
}
}
输出:
74
例 3 :
// Java code for LongStream max()
// to get the maximum value in range
// excluding the last element
import java.util.*;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// To find maximum in given range
LongStream stream = LongStream.range(50L, 50L);
// storing the maximum value in variable
// if it is present, else show -1.
long maximum = stream.max().orElse(-1);
// displaying the maximum value
System.out.println(maximum);
}
}
输出:
-1
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