什么是此Linq查詢等效的C＃擴展方法？

Question

在這個例子中：

public void Linq40()
{
    int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

    var numberGroups =
        from n in numbers
        group n by n % 5 into g
        select new { Remainder = g.Key, Numbers = g };

    foreach (var g in numberGroups)
    {
        Console.WriteLine("Numbers with a remainder of {0} when divided by 5:",
            g.Remainder);

        foreach (var n in g.Numbers)
        {
            Console.WriteLine(n);
        }
    }
}

什么是純粹的c＃等價物？ 我明白了......

var numberGroups = numbers.GroupBy(n => n % 5)...

但是into子句有點神秘，我無法弄清楚如何從Select獲取Key 。

Answer 1

numbers.GroupBy(n => n % 5).Select(g => new { Remainder = g.Key, Numbers = g });

Answer 2

GroupBy返回<IGrouping<TKey, TSource>的IEnumerable<T> <IGrouping<TKey, TSource> 。 有了這個，你可以做第二個Select操作，它返回與上面完全相同的值：

var numberGroups = numbers.GroupBy(n => n % 5)
                          .Select(g => new { Remainder = g.Key, Numbers = g });