使用 C# 将多个值分组到一个序列中

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要求提供代码的问题必须表现出对所解决问题的最低限度的了解。包括尝试的解决方案、为什么它们不起作用以及预期结果。另请参阅：Stack Overflow 问题清单

已关闭 11 年前。

Answer 1

我的方法是使用正则表达式来解析数据，然后使用 linq 对其进行分组。您能向我们展示您到目前为止所做的尝试吗？

Answer 2

下面是一个您可以尝试的实现。

class UserLanguage
{
    public string UserName { get; set; }

    public string Language { get; set; }
}

static class EnumerableExtensions
{
    public static string Concatenate(this IEnumerable<string> source, string delimiter)
    {
        using (var enumerator = source.GetEnumerator())
        {
            if (enumerator.MoveNext())
            {
                StringBuilder builder = new StringBuilder(enumerator.Current);
                while (enumerator.MoveNext())
                {
                    builder.Append(delimiter).Append(enumerator.Current);
                }
                return builder.ToString();
            }
            else
            {
                return null;
            }
        }
    }
}

class Program
{
    static void Main(string[] args)
    {
        // assuming that you already have data stored in a structure similar to this
        var rawData = new List<UserLanguage>()
        {
            new UserLanguage { UserName = "Bob", Language = "English" },
            new UserLanguage { UserName = "Bob", Language = "French" },
            new UserLanguage { UserName = "Alan", Language = "Italian" },
            new UserLanguage { UserName = "Alan", Language = "Spanish" },
            new UserLanguage { UserName = "Alan", Language = "German" },
        };

        // group these objects together by UserName
        var groupedData = rawData.GroupBy(userLanguage => userLanguage.UserName);

        foreach (var grouping in groupedData)
        {
            Console.WriteLine(grouping.Key + "\t" + grouping.Select(userLanguage => userLanguage.Language).Concatenate("/"));
        }
    }
}

Answer 3

class Person
{
    string UserName {get; set;}
    string LanguageSpoken {get; set;}    
}

var table = new List<Person>() {
    new Person() {
        UserName = "Bob";
        LanguageSpoken = "English"
    }
    /* next persons*/
};

var userNameGroups = from n in table
    group n by n.UserName into g
    select new {
        keyUserName = g.Key,
        LanguageSpoken = g
    };

foreach(var g in userNameGroups) {
    Console.Write(g.keyUserName.ToString());
    foreach(var n in g.LanguageSpoken) {
        Console.WriteLine(n.ToString());
    }
}

Answer 4

如果您的列表类似于：

class Person
{
    public string Name { get; set; }
    public string Language { get; set; }
}

List<Person> myList = /* Initialization */

那么 LINQ GroupBy 应该可以解决问题：

myList.GroupBy(a => a.Name);

希望这会有所帮助。