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Student.java
package com.stream2;
import lombok.AllArgsConstructor;
import lombok.Data;
@Data
@AllArgsConstructor
public class Student {
private String name;
private int score;
}
Java
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•
StreamExample.java
package com.stream2;
import java.util.Arrays;
import java.util.List;
import java.util.OptionalDouble;
import java.util.stream.IntStream;
import java.util.stream.Stream;
public class StreamExample {
public static void main(String[] args) {
List<Student> sList = Arrays.asList(
new Student("Alice", 90),
new Student("Bob", 80),
new Student("Jonathan", 85),
new Student("David", 95)
);
// Stream<Student> originalStream = sList.stream();
// IntStream intStream = originalStream.mapToInt(Student::getScore);
// OptionalDouble optAverage = intStream.average();
// double avg = optAverage.getAsDouble();
double avg = sList.stream()
.mapToInt(Student::getScore). // s -> s.getScore()
.average()
.getAsDouble();
System.out.println(avg);
}
}
Java
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