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c# - 如何将元组列表与 3 个项目组合在一起，其中 element.item3 == element2.item2

问题描述

我有以下问题：需要对List<Tuple<object, int, int>>不同元素的 item3 等于 item2 进行分组，如果有任何不匹配的元素，它们应该留在当前位置！更加具体List<Tuple<UserDescription, userId, inviterId>>

我尝试过使用 LINQ 的不同方法 - 分组、选择、位置，但没有成功......

var list = new List<Tuple<object, int, int>> // item2 - UserId, item3 - InviterId
    {
        new Tuple<object, int, int>(new { Name = "Ivan" }, 1, 12),
        new Tuple<object, int, int>(new { Name = "George" }, 2, 3),
        new Tuple<object, int, int>(new { Name = "Phil" }, 3, 12),
        new Tuple<object, int, int>(new { Name = "John" }, 4, 3),
        new Tuple<object, int, int>(new { Name = "Giggs" }, 5, 1),
        new Tuple<object, int, int>(new { Name = "Higgins" }, 6, 1)
    };

预期的结果应该是分组元组。Ivan 应该留在当前，因为没有用户 ID 为 12 的用户。他下面应该是 Giggs 和 Higgins，因为他们的邀请者 ID 是 1（Ivan 的用户 ID）等等。结果：

Ivan (user id = 1)
 Giggs (inviter id = 1)
 Higgins (inviter id = 1)
Phil (user id = 3)
 George (inviter id = 3)
 John (inviter id = 3)

标签： c#algorithmlinqsortinggrouping

解决方案

这是我的尝试。注意：此代码假定您的列表索引 = UserId。

var list = new List<Tuple<object, int, int>> // item2 - UserId, item3 - InviterId
        {
            new Tuple<object, int, int>(new { Name = "Ivan" }, 1, 12),
            new Tuple<object, int, int>(new { Name = "George" }, 2, 3),
            new Tuple<object, int, int>(new { Name = "Phil" }, 3, 12),
            new Tuple<object, int, int>(new { Name = "John" }, 4, 3),
            new Tuple<object, int, int>(new { Name = "Giggs" }, 5, 1),
            new Tuple<object, int, int>(new { Name = "Higgins" }, 6, 1)
        };

        var grouped = list.ToLookup(t => t.Item2);

        var withInviter = grouped.Select(grp => Tuple.Create(list[grp.Key], grp));

        var sorted = withInviter.OrderBy(t => t.Item1.Item2);

编辑：对不起，但是当我再次阅读您的示例时，我发现我误解了您正在寻找的结果。我好像可以把用户分为邀请和不邀请？我会更新我的答案，因为它不正确。

编辑2：这个应该工作：

    struct InviterAndInvited {
        public Tuple<object, int, int> Inviter;
        public IEnumerable<Tuple<object, int, int>> Invited;
    }

    public static void Main(string[] args)
    {
        var list = new List<Tuple<object, int, int>> // item2 - UserId, item3 - InviterId
        {
            new Tuple<object, int, int>(new { Name = "Ivan" }, 1, 12),
            new Tuple<object, int, int>(new { Name = "George" }, 2, 3),
            new Tuple<object, int, int>(new { Name = "Phil" }, 3, 12),
            new Tuple<object, int, int>(new { Name = "John" }, 4, 3),
            new Tuple<object, int, int>(new { Name = "Giggs" }, 5, 1),
            new Tuple<object, int, int>(new { Name = "Higgins" }, 6, 1)
        };

        var byInviter = list.ToLookup(u => u.Item3);

        var inviterInveted = list
            .Where(user => byInviter.Contains(user.Item2))
            .Select(user => new InviterAndInvited() {
                Inviter = user,
                Invited = byInviter[user.Item2] 
            } );

        foreach (var grp in inviterInveted) // Print results
        {
            Console.WriteLine(grp.Inviter.Item1);
            foreach (var user in grp.Invited) {
                Console.WriteLine("\t" + user.Item1);
            }
        }
    }

编辑 4：将 GetOrDefault 更改为 []

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