list 常见的统计(求和、最大、最小、平均)

时间:2024-11-18 07:21:33

list 常见的统计(求和、最大、最小、平均)

package .list_test;

import ;
import ;

/**
 * 描述:ListTest3
 *
 * @author 何志鹏
 * @ClassName:ListTest3
 * @create 2019-05-30 18:49
 * Version 1.0
 */
public class ListTest3 {
    public static void main(String[] args) {
        List<Student>  list  = new ArrayList<>();
         Student s1 = new Student();
        (1);
        ("张三");
        (28);

        Student s2 = new Student();
        (2);
        ("李四");
        (29);

        Student s3 = new Student();
        (3);
        ("网二");
        (30);

        (s1);
        (s2);
        (s3);

        ("=========第一种方式================");
        int suma =  ().map(e -> ()).reduce(Integer::sum).get();//求和
        (suma);
        int maxa =  ().map(e -> ()).reduce(Integer::max).get();//最大
        (maxa);
        int mina =  ().map(e -> ()).reduce(Integer::min).get();//最小
        (mina);

        ("=========第二种方式================");

        double doublesum =  ().mapToDouble(Student::getAge).sum();//和
        (doublesum);
        int intmax = ().mapToInt(Student::getAge).max().getAsInt();//最大
        (intmax);
        int intmin = ().mapToInt(Student::getAge).min().getAsInt();//最小
        (intmin);
        double avg =  ().mapToDouble(Student::getAge).average().getAsDouble();//平均
        (avg);




    }
}