Java 中的 intstream maptolong()
哎哎哎:# t0]https://www . geeksforgeeks . org/intstream-map olong-Java/
IntStream mapToLong() 返回一个 LongStream，该 LongStream 由给定函数应用于该流元素的结果组成。
注意: IntStream mapToLong()是一个 的中间操作。 这些操作总是偷懒。中间操作在流实例上被调用，在它们完成处理后，它们给出一个流实例作为输出。 语法:
LongStream mapToLong(IntToLongFunction mapper)
参数:
- LongStream : 原始长值元素的序列。这是溪流漫长的原始特化。
- 映射器:应用于每个元素的无状态函数。
返回值:函数返回一个 LongStream，该 LongStream 由给定函数应用于该流元素的结果组成。
例 1 :
// Java code for LongStream mapToLong
// (IntToLongFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating an IntStream
IntStream stream = IntStream.of(2, 4, 6, 8, 10);
// Using LongStream mapToLong(IntToLongFunction mapper)
// to return a LongStream consisting of the
// results of applying the given function to
// the elements of this stream.
LongStream stream1 = stream.mapToLong(num -> (long)num);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
2
4
6
8
10
例 2 :
// Java code for LongStream mapToLong
// (IntToLongFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating an IntStream
IntStream stream = IntStream.of(2, 4, 6, 8, 10);
// Using LongStream mapToLong(IntToLongFunction mapper)
// to return a LongStream consisting of the
// results of applying the given function to
// the elements of this stream.
LongStream stream1 = stream.mapToLong(num -> (long)num + Integer.MAX_VALUE);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
2147483649
2147483651
2147483653
2147483655
2147483657
例 3 :
// Java code for LongStream mapToLong
// (IntToLongFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating an IntStream
IntStream stream = IntStream.range(5, 10);
// Using LongStream mapToLong(IntToLongFunction mapper)
// to return a LongStream consisting of the
// results of applying the given function to
// the elements of this stream.
LongStream stream1 = stream.mapToLong(num -> (long)num - 20);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
-15
-14
-13
-12
-11
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