Question

我会解释，我正在做一个简单的琐事。我需要在一个数组中得到3个错误答案和1个正确答案。我声明哈希表并用数据填充它：

 private static readonly HashSet<string> DifferentAnswers= new HashSet<string>();

此HashSet包含类别的所有可能答案，包括正确答案。

目前，我正在执行以下操作以获得3个错误答案：

注意：CorrectAnswer变量是字符串类型中的绝对正确答案

DifferentAnswers
  .OrderBy(n => Guid.NewGuid())
  .Take(3)
  .Where(n => n != CorrectAnswer)
  .ToArray();

有没有办法在1个花式Linq（共4项）中以不同的顺序将3个不正确的答案和1个正确的答案输入数组？：）

之后我将检查阵列中正确答案的数量。

Answer 1

你可以“联合” IEnumerable的其他项目列表，但您可能希望事后重新洗牌：

DifferentAnswers
  .OrderBy(n => Guid.NewGuid())
  .Where(n => n != CorrectAnswer)
  //Needs to be after the Where
  .Take(3)
  // added:
  .Concat(new [] {CorrectAnswer})
  .OrderBy(n => Guid.NewGuid())
  //
  .ToArray();

（当然，它假设您事先了解CorrectAnswer，就像您建议的示例代码一样）

Answer 2

看看这是否有帮助：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication51
{
    class Program
    {
        public class Question
        {
            public int number { get; set; }
            public string question { get; set; }
            public string answer { get; set; }
            public List<string> wrongAnswer { get; set; }
        }

        static void Main(string[] args)
        {
            List<Question> test = new List<Question>() {
                new Question() { number = 1, question = "Question 1", answer = "Answer 1", wrongAnswer = new List<string>() { "Wrong Answer 1","Wrong Answer 2","Wrong Answer 3"}},
                new Question() { number = 2, question = "Question 2", answer = "Answer 2", wrongAnswer = new List<string>() { "Wrong Answer 1","Wrong Answer 2","Wrong Answer 3"}},
                new Question() { number = 3, question = "Question 3", answer = "Answer 3", wrongAnswer = new List<string>() { "Wrong Answer 1","Wrong Answer 2","Wrong Answer 3"}},
                new Question() { number = 4, question = "Question 4", answer = "Answer 4", wrongAnswer = new List<string>() { "Wrong Answer 1","Wrong Answer 2","Wrong Answer 3"}},
                new Question() { number = 5, question = "Question 5", answer = "Answer 5", wrongAnswer = new List<string>() { "Wrong Answer 1","Wrong Answer 2","Wrong Answer 3"}}
            };

            Random rand = new Random();

            var results = test.OrderBy(x => x.number).Select(x => new List<KeyValuePair<int,string>>() { new KeyValuePair<int,string>(rand.Next(), x.answer), new KeyValuePair<int,string>(rand.Next(), x.wrongAnswer[0]),new KeyValuePair<int,string>(rand.Next(), x.wrongAnswer[1]),new KeyValuePair<int,string>(rand.Next(), x.wrongAnswer[2])})
                .Select(x => x.OrderBy(y => y.Key).Select(y => y.Value).ToList()).ToList();

        }
    }
}

从HashSet中获取3个随机元素和1个预设元素

2 个答案: