Java Streams - DoubleStream mapToLong (DoubleToLongFunction mapper)

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DoubleStream mapToLong(DoubleToLongFunction mapper) returns a LongStream by applying the given function to the elements of this stream. This is an intermediate operation.

Syntax

mapToLong has the following syntax.

LongStream mapToLong(DoubleToLongFunction mapper)

Example

The following example shows how to use mapToLong.

import java.util.stream.DoubleStream;

public class Main {
  public static void main(String[] args) {
    DoubleStream b = DoubleStream.of(1.1,2.2,3.3,4.4,5.5);
    b.mapToLong(n -> {return (long) (n*n);})
     .forEach(System.out::println);
  }
}

The code above generates the following result.

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