LINQ(Language-Integrated Query) 쿼리 결과 Object로 반환

간단하게 테스트 가능한 코드를 보여준다.

using System;
using NUnit.Framework;
using System.Collections.Generic;
using System.Linq;

namespace LinqQueryTest
{
    public class LinqCollectionObject
    {
        [Test]
        public void CollectionOfObjects()
        {
            var scores = Student.QueryHighScores(1, 90);

            scores.ForEach(Console.WriteLine);

            Assert.AreEqual(4, scores.Count);

        }
    }

    public class Student
    {
        #region data

        public enum GradeLevel
        {
            FirstYear = 1,
            SecondYear,
            ThirdYear,
            FourthYear
        };

        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Id { get; set; }
        public GradeLevel Year;
        public List<int> ExamScores;

        protected static List<Student> students = new List<Student>
        {
            new Student
            {
                FirstName = "Terry", LastName = "Adams", Id = 120,
                Year = GradeLevel.SecondYear,
                ExamScores = new List<int> {99, 82, 81, 79}
            },
            new Student
            {
                FirstName = "Fadi", LastName = "Fakhouri", Id = 116,
                Year = GradeLevel.ThirdYear,
                ExamScores = new List<int> {99, 86, 90, 94}
            },
            new Student
            {
                FirstName = "Hanying", LastName = "Feng", Id = 117,
                Year = GradeLevel.FirstYear,
                ExamScores = new List<int> {93, 92, 80, 87}
            },
            new Student
            {
                FirstName = "Cesar", LastName = "Garcia", Id = 114,
                Year = GradeLevel.FourthYear,
                ExamScores = new List<int> {97, 89, 85, 82}
            },
            new Student
            {
                FirstName = "Debra", LastName = "Garcia", Id = 115,
                Year = GradeLevel.ThirdYear,
                ExamScores = new List<int> {35, 72, 91, 70}
            },
            new Student
            {
                FirstName = "Hugo", LastName = "Garcia", Id = 118,
                Year = GradeLevel.SecondYear,
                ExamScores = new List<int> {92, 90, 83, 78}
            },
            new Student
            {
                FirstName = "Sven", LastName = "Mortensen", Id = 113,
                Year = GradeLevel.FirstYear,
                ExamScores = new List<int> {88, 94, 65, 91}
            },
            new Student
            {
                FirstName = "Claire", LastName = "O'Donnell", Id = 112,
                Year = GradeLevel.FourthYear,
                ExamScores = new List<int> {75, 84, 91, 39}
            },
            new Student
            {
                FirstName = "Svetlana", LastName = "Omelchenko", Id = 111,
                Year = GradeLevel.SecondYear,
                ExamScores = new List<int> {97, 92, 81, 60}
            },
            new Student
            {
                FirstName = "Lance", LastName = "Tucker", Id = 119,
                Year = GradeLevel.ThirdYear,
                ExamScores = new List<int> {68, 79, 88, 92}
            },
            new Student
            {
                FirstName = "Michael", LastName = "Tucker", Id = 122,
                Year = GradeLevel.FirstYear,
                ExamScores = new List<int> {94, 92, 91, 91}
            },
            new Student
            {
                FirstName = "Eugene", LastName = "Zabokritski", Id = 121,
                Year = GradeLevel.FourthYear,
                ExamScores = new List<int> {96, 85, 91, 60}
            }
        };

        #endregion

        // Helper method, used in GroupByRange.
        protected static int GetPercentile(Student s)
        {
            double avg = s.ExamScores.Average();
            return avg > 0 ? (int) avg / 10 : 0;
        }

        public static List<ScoreResult> QueryHighScores(int exam, int score)
        {
            var highScores = from student in students
                where student.ExamScores[exam] > score
                select new ScoreResult {Name = student.FirstName, Score = student.ExamScores[exam]};

            return highScores.ToList();
        }
    }

    public record ScoreResult
    {
        public string Name { get; set; }

        public int Score { get; set; }
    }
}

참조

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• linq