特定范圍內的按日期分組

Question

假設我有以下內存中的項目和日期集合：

ItemID: 1, Date: 10/10/2018 11:30 AM
ItemID: 1, Date: 10/10/2018 11:32 AM
ItemID: 1, Date: 10/10/2018 11:33 AM
ItemID: 1, Date: 10/10/2018 11:34 AM
ItemID: 1, Date: 10/10/2018 11:57 AM
ItemID: 2, Date: 10/10/2018 7:45 AM
ItemID: 2, Date: 10/10/2018 7:49 AM
ItemID: 3, Date: 10/10/2018 8:45 AM
ItemID: 3, Date: 10/10/2018 9:13 AM

我想按ItemID和Date進行分組，但是我希望它們分組的日期在最低日期的5分鍾內，在這種情況下，項目1最低時間是：11：30 AM在接下來的幾分鍾11:30 + 5分鍾之間

在上面的數據集中，將對以下內容進行分組

ItemID: 1, Date: 10/10/2018 11:30 AM    <-- Grouped with Item 1
ItemID: 1, Date: 10/10/2018 11:32 AM    <-- Grouped with Item 1
ItemID: 1, Date: 10/10/2018 11:33 AM    <-- Grouped with Item 1
ItemID: 1, Date: 10/10/2018 11:34 AM    <-- Grouped with Item 1


ItemID: 1, Date: 10/10/2018 11:57 AM    <-- Not Grouped


ItemID: 2, Date: 10/10/2018 7:45 AM    <-- Grouped with Item 2
ItemID: 2, Date: 10/10/2018 7:49 AM    <-- Grouped with Item 2


ItemID: 3, Date: 10/10/2018 8:45 AM    <-- Not Grouped

ItemID: 3, Date: 10/10/2018 9:13 AM    <-- Not Grouped

分組的是彼此相差5分鍾的那些。

OUTPUT：

Item 1:
Date: 10/10/2018 11:30 AM    <--- Lowest Minute is 30 so 30 + 5 range group
Date: 10/10/2018 11:32 AM
Date: 10/10/2018 11:33 AM
Date: 10/10/2018 11:34 AM

Item 1:
Date: 10/10/2018 11:57 AM

Item 2:
Date: 10/10/2018 7:45 AM
Date: 10/10/2018 7:49 AM

Item 3:
Date: 10/10/2018 8:45 AM

Item 3:
Date: 10/10/2018 9:13 AM

Answer 1

您可以先按ID分組，然后按照最小組時間除以間隔而沒有提醒的總分鍾數對每個組進行分組：

var interval = 5;
var groupedItems = items
    .GroupBy(i => i.ItemId, (k, g) => g
        .GroupBy(i => (long)(i.Date - g.Min(e => e.Date)).TotalMinutes / interval))
    .SelectMany(g => g);

Answer 2

這是一個非常粗略的例子，我把它放在一起得到你想要的“輸出”。 當然將它應用到您的情況並添加您自己的錯誤檢查/驗證/訂購/等等。我也沒有使用LINQ，因為我認為根據您的評論不合適。 最后，我沒有完全匹配您的輸出。 我覺得這可能是某種類型的任務。 如果是這樣，那么你肯定可以進行那么小的調整。

支持類：

class Item
{
    public int ItemID { get; set; }
    public DateTime Date { get; set; }
}

示例方法：

private static void Example()
{
    var myList = new List<Item>
    {
        new Item {ItemID = 1, Date = DateTime.Parse("10/10/2018 11:30 AM") },
        new Item {ItemID = 1, Date = DateTime.Parse("10/10/2018 11:32 AM") },
        new Item {ItemID = 1, Date = DateTime.Parse("10/10/2018 11:33 AM") },
        new Item {ItemID = 1, Date = DateTime.Parse("10/10/2018 11:34 AM") },
        new Item {ItemID = 1, Date = DateTime.Parse("10/10/2018 11:57 AM") },
        new Item {ItemID = 2, Date = DateTime.Parse("10/10/2018 7:45 AM") },
        new Item {ItemID = 2, Date = DateTime.Parse("10/10/2018 7:49 AM") },
        new Item {ItemID = 3, Date = DateTime.Parse("10/10/2018 8:45 AM") },
        new Item {ItemID = 3, Date = DateTime.Parse("10/10/2018 9:13 AM") }
    };

    Item baseItem = myList.First();
    int currentGroup = 1;

    // output first group
    Console.WriteLine($"Group {currentGroup}");

    foreach (var item in myList) // .OrderBy(i=>i.ItemID).ThenBy(i => i.Date))
    {
        // if item is different OR date is >5mins from the first
        if (item.ItemID != baseItem.ItemID || item.Date > baseItem.Date.AddMinutes(5))
        {
            // different group
            currentGroup += 1;

            // set new base item
            baseItem = item;

            Console.WriteLine($"\nGroup {currentGroup}");// output new group
        }

        // output the item
        Console.WriteLine($"Item {item.ItemID}. Date: {item.Date}");
    }
}

輸出：

Group 1
Item 1. Date: 10/10/2018 11:30:00 AM
Item 1. Date: 10/10/2018 11:32:00 AM
Item 1. Date: 10/10/2018 11:33:00 AM
Item 1. Date: 10/10/2018 11:34:00 AM

Group 2
Item 1. Date: 10/10/2018 11:57:00 AM

Group 3
Item 2. Date: 10/10/2018 7:45:00 AM
Item 2. Date: 10/10/2018 7:49:00 AM

Group 4
Item 3. Date: 10/10/2018 8:45:00 AM

Group 5
Item 3. Date: 10/10/2018 9:13:00 AM

Answer 3

這里有一個功能齊全的工作示例，說明如何解決這個問題與前兩個答案一致。 只需打開VS並創建一個新的ConsoleApp並粘貼這些東西並試一試。 希望你現在能找到自己的方式。

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp3
{
    public class Item
    {
        public int ItemID { get; set; }
        public DateTime Date { get; set; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            List<Item> items = new List<Item>
            {
                new Item { ItemID= 1, Date = new DateTime(2018, 10, 10, 11, 30, 0) },
                new Item { ItemID= 1, Date = new DateTime(2018, 10, 10, 11, 32, 0) },
                new Item { ItemID= 1, Date = new DateTime(2018, 10, 10, 11, 33, 0) },
                new Item { ItemID= 1, Date = new DateTime(2018, 10, 10, 11, 34, 0) },
                new Item { ItemID= 1, Date = new DateTime(2018, 10, 10, 11, 57, 0) },
                new Item { ItemID= 2, Date = new DateTime(2018, 10, 10, 7, 45, 0) },
                new Item { ItemID= 2, Date = new DateTime(2018, 10, 10, 7, 49, 0) },
                new Item { ItemID= 2, Date = new DateTime(2018, 10, 10, 8, 45, 0) },
                new Item { ItemID= 2, Date = new DateTime(2018, 10, 10, 9, 13, 0) }
            };

            var groupedItems = items.GroupBy(i => i.ItemID, (k, g) => g
          .GroupBy(i => (long)new TimeSpan(i.Date.Ticks - g.Min(e => e.Date).Ticks).TotalMinutes / 5));

            var groupIndex = 0;
            foreach (var group in groupedItems)
            {
                foreach (IGrouping<long, Item> groupItem in group)
                {
                    Console.Out.WriteLine("Group " + (++groupIndex));

                    foreach (var item in groupItem)
                    {
                        Console.WriteLine($"Item {item.ItemID}. Date: {item.Date}");

                    }
                    Console.Out.WriteLine();
                }
            }
            Console.ReadLine();
        }
    }
}

干杯