使用linq将订单列表分组的订单 [英] List of Orders to Grouped Orders using linq

问题描述

我有一个像这样的班级订单

I have a class Order like

class Order
{
   IEnumerable<Item> Items { get; set; }
}

物品类看起来像

class Item
{
   string SomeProperty { get; set; } 
   string SomeProperty1 { get; set; } 
   string SomeProperty2 { get; set; } 
}

模型是类似于

@model IEnumerable<Order>

我想以一个顺序对相同的项进行分组，这意味着在Item.SomeProperty

I want to group same Items in one order means grouping on Item.SomeProperty

我可以通过将(收藏夹列表归为分组收藏夹列表来实现此目的使用linq )

var orderedGroups = Model
    .SelectMany(order => order.Items)
    .GroupBy(order => order.ItemNo)
    .OrderByDescending(grp => grp.Count()).ToList();

为此，我要确保所有组具有相同的项目数，具体取决于最大数量，并向计数较低的组添加空白"结果，但我不知道如何继续进行.

With this I want to make sure all groups have the same number of items, depending on the maximum count and adding "blank" results to the groups which has lower count but I don't know how to proceed further.

推荐答案

需求很奇怪，不确定用例，但这是我要实现的方式:

Requirements are quite strange, not sure of the use case, but this is how I would achieve it:

var orderedGroups = Model
    .SelectMany(order => order.Items)
    .GroupBy(order => order.ItemNo)
    .OrderByDescending(order => order.Count())
    .ToDictionary(order => order.Key, order => order.ToList());

假设ItemNo是字符串，

orderedGroups的类型将为Dictionary<string,List<Item>>

orderedGroups will be of type Dictionary<string,List<Item>>, assuming ItemNo is a string

获取Descending sorted collection中的最大元素数:

var maxElements = orderedGroups.First().Value.Count; // Max elements collection is at the top

foreach (var x in orderedGroups.Skip(1)) // Skip the processing of first collection, as that has maximum number of elements
        {       
            int yMax = maxElements - x.Value.Count ; // Count of each Item collection

            for (int y = 0; y < yMax; y++)
            {
                x.Value.Add(default(Item)); // Adding `default Item`, replace with any standard value
            }
        }

使用Integer代替Item的另一个工作版本的代码:

Another working version of code using Integer in place of Item:

List<int> testList = new List<int> {1,2,3,4,1,3,5,6,3,6,4,2,1,3,7,7,7,7,7,7,7};

        var orderedGroups = testList.GroupBy(x => x)
                                    .OrderByDescending(x => x.Count())
                                    .ToDictionary(x => x.Key, x => x.ToList());


        var maxElements = orderedGroups.First().Value.Count;


        foreach (var x in orderedGroups.Skip(1))
        {       
            int yMax = maxElements - x.Value.Count;

            for (int y = 0; y < yMax; y++)
            {
                x.Value.Add(0); // Adding default as 0
            }
        }


    orderedGroups.Dump(); // Linqpad print call, replace with console or similar call in the visual studio

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