Question

我有两个2D数组，我试图比较并删除其中一个重复数据。我知道如何从1D数组中删除重复项，但我从未尝试过使用两个2D数组，我希望有人知道一种方法来完成这项工作。对于1D阵列，我会完成img，但是2d阵列似乎没有相同的工作方式:(这是我正在使用的数据类型：

字段是两者的文字和日期，我的主要目标是能够从＆＃34; elMultiArray＆＃34;与＆＃34; fMultiArray＆＃34;匹配的那些

这是我尝试完成的一个例子：

alter FUNCTION [dbo].[CalcWorkDaysAddDays_inline](@StartDate As DateTime,@Days AS INT) 
returns table 
as return
with cte as
(
select *,
       ROW_NUMBER() over(order by Calendar_Date) as rn
from RRCP_Calendar
where Calendar_Date > @StartDate and @Days > 0
      and not (DATEPART(WEEKDAY,Calendar_Date) IN (1,7) or Is_Holiday = 1)

union ALL

select *,
       ROW_NUMBER() over(order by Calendar_Date desc) as rn
from RRCP_Calendar
where Calendar_Date < @StartDate and @Days < 0
      and not (DATEPART(WEEKDAY,Calendar_Date) IN (1,7) or Is_Holiday = 1)


)
select cast(Calendar_Date as date) as dt
from cte
where rn = abs(@Days);

有人会这么善意至少给我这方面的指示吗？在此先感谢所有人。

Answer 1

鉴于.NET框架中可用的数据结构大大改进，二维数组的数据结构非常糟糕。但是，你表示你出于某种原因必须使用它们，所以就这样了。

通常我们在单个LINQ语句中执行此操作。但是LINQ没有2D数组方法。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1 {
    class Program {
        static void Main(string[] args) {
            string[,] array1 = { { "123", "09/17/17" }, { "456", "09/17/17" }, { "789", "09/18/17" } };
            string[,] array2 = { { "147", "09/17/17" }, { "789", "09/20/17" }, { "123", "09/19/17" } };
            //Output: string[,] array 3 = {456, 09/17/17}

            List<string> keys = new List<string>();
            Dictionary<string, string> output = new Dictionary<string, string>();

            // grab the first-dimension values
            for(int index =0; index < array2.GetLength(0);index++) {
                keys.Add( array2[index, 0]);
            }

            // compare they first-dimension values that we extracted to the first-dimension values in the 
            // source array.  If no match is found, then it is not a duplicate entry, so record it in
            // the output container.
            for (int index = 0; index < array1.GetLength(0); index++) {
                if (!keys.Contains(array1[index,0])) {
                    output.Add(array1[index, 0], array1[index, 1]);
                }
            }

            // transforming the output Dictionary<> into a 2D array is left as an excersize for the reader.

            // print output
            foreach(var key in output.Keys) {
                Console.WriteLine($"{key}: {output[key]}");
            }
            Console.ReadKey(true);
        }
    }
}

Answer 2

linq不支持2D数组，但您可以编写可迭代的Except2D()并生成Tuple<string, string>。您可以使用HashSet<string>存储重复的密钥。 Add函数可用于检查密钥是否已存在。

static void Main(string[] args)
{
    string[,] array1 = { { "123", "09/17/17" }, { "456", "09/17/17" }, { "789", "09/18/17" } };
    string[,] array2 = { { "147", "09/17/17" }, { "789", "09/20/17" }, { "123", "09/19/17" } };

    // .ToArray() not required when only iterating once
    // and .Length is not required
    var elements = array1.Except2D(array2).ToArray();

    // make it a 2D array, if required
    string[,] combined = new string[elements.Length, 2];
    for (int i = 0; i < elements.Length; i++)
    {
        combined[i, 0] = elements[i].Item1;
        combined[i, 1] = elements[i].Item2;
    }

    Console.ReadLine();
}

static IEnumerable<Tuple<string, string>> Except2D(this string[,] a, string[,] b)
{
    HashSet<string> keys = new HashSet<string>();
    for (int index = 0; index < a.GetLength(0); index++)
    {
        if(keys.Add(a[index, 0]))
        {
            yield return new Tuple<string, string>(a[index, 0], a[index, 1]);
        }
    }
}

如何从两个不同的2d数组中删除重复项

2 个答案: