将另一列表中的对象分配给另一组列表

Question

我有一份清单。

public List<Objects> obj;

此列表中的对象需要添加到这些其他列表中。

public List<Objects> objGroup1, objGroup2, objGroup3, objGroup4; 

我现在就给他们分配这个。

void AssignToGroups()
{
    for(int i = 0; i < obj.Count ; i++)
    {
//Need the first 4 for group 1 next 4 for group 2 and so on...

        if(i < 4)
        {
            objGroup1.Add(obj[i]);
        }

        else if(i >= 4 && i < 8)
        {
            objGroup2.Add(obj[i]);
        }

        else if (i >= 8 && i < 12)
        {
            objGroup3.Add(obj[i]);
        }

        else if (i >= 12 && i < 16)
        {
            objGroup4.Add(obj[i]);
        }
    }
}

我正在计划展开，我现在对对象进行分组的方法将使我的屏幕上充满没完没了的if和else语句。

每个组需要分配4个对象。组中的对象按照它们的排列顺序得到它们。例如，group1得到obj 1-4。第二组5-8，等等.

有谁有更好的方法来分组这样的对象吗？

Answer 1

您可以使用跳过和拿走方法。

你需要using System.Linq;

objGroup1 = obj.Take(4).ToList();           //edited: use ToList() to keep the list format
objGroup2 = obj.Skip(4).Take(4).ToList();
objGroup3 = obj.Skip(8).Take(4).ToList();    
objGroup4 = obj.Skip(12).Take(4).ToList();
objGroup5 = obj.Skip(16).Take(4).ToList();

让我知道它是否工作，因为我现在无法测试它，除了语法。

还可以在obj之前对Take()进行分组，如

var orderedobj = obj.OrderBy(i => "some order criteria").ToList();
objGroup1 = orderedobj.Take(4);
...

我在如何在C#中获得列表的第一个N个元素？上引用了我的答案。

编辑：

如果您不想使用Linq，也可以使用GetRange。

objGroup1 = obj.GetRange(0, 4);
objGroup2 = obj.GetRange(3, 4);     //since GetRange(index, count) has index starting from 0 instead of 1
objGroup3 = obj.GetRange(7, 4);     //count stays the same since we always want 4 elements
objGroup4 = obj.GetRange(11, 4);
objGroup5 = obj.GetRange(15, 4);

Answer 2

使用Keyur的出色答案，您可以创建一个方法，该方法将根据任何源列表为您创建组，并具有可配置的组大小：

private static List<List<object>> AssignToGroups(List<object> source, int groupSize)
{
    var groups = new List<List<object>>();

    if (source == null || groupSize < 1) return groups;

    for (int i = 0; i < source.Count / groupSize; i++)
    {
        groups.Add(source.Skip(groupSize * i).Take(groupSize).ToList());
    }

    return groups;
}

使用

private static void Main()
{
    var mainList = new List<object>
    {
        "one", "two", "three", "four","five",
        "six","seven","eight","nine","ten",
        "eleven", "twelve", "thirteen", "fourteen","fifteen",
        "sixteen","seventeen","eightteen","nineteen","twenty",
        "twentyone", "twentytwo", "twentythree", "twentyfour","twentyfive",
        "twentysix","twentyseven","twentyeight","twentynine","thirty",
        "thirtyone", "thirtytwo", "thirtythree", "thirtyfour","thirtyfive",
        "thirtysix","thirtyseven","thirtyeight","thirtynine","forty",
    };

    var groups = AssignToGroups(mainList, 4);

    for (var i = 0; i < groups.Count; i++)
    {
        Console.WriteLine($"Group #{i + 1}: {string.Join(", ", groups[i])}");
    }

    Console.WriteLine("\nDone!\nPress any key to exit...");
    Console.ReadKey();
}

输出

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