如何比较两个列表，以及它们是否具有相等的值，取列表的两个索引

Question

如何比较两个列表，并说如果这两个列表具有相等的值，则对两个不同的点进行索引，并在该索引处从两个不同列表中吐出另外两个列表值。两个列表都有相同数量的值——应该比较的两个列表中都有id，而应该写出值的另外两个列表则有categoryNames。我的代码如下。。。

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Office.Interop.Excel;
namespace PrestaConverter
{
public class ExcellCreation
{
#region privata variabler
/// <summary>
/// WhatExcelFile Håller reda på Vilken excelfil som ska sparas, 
/// Name Namnet på sparfilen,
/// count är en räknare som ger id till Kategorierna
/// </summary>
Hashtable myHashtable = new Hashtable();
private int WhatExcellFile;
private string name = "CategoriesCatalog";
private List<string> ColumnNames = new List<string>() {"ID",
"Active(0/1)",
"Name*",
"Parent Category",
"Root Category(0/1)",
"Description",
"Meta title",
"Meta keywords",
"Meta description",
"URL rewritten",
"Image URL"
};
private Categories categories1 = new Categories();
private Categories categories2 = new Categories();
private Categories categories3 = new Categories();
private int count;
ExcelConverter converter = new ExcelConverter(); 
#endregion
#region Skapa excel
/// <summary>
/// Funktion som skapar de nya Excelfilerna 
/// </summary>
/// <param name="excelValue">Kategorinamnen sänds över till denna funktion för upplägg i ny fil</param>
/// <param name="rowAmmount">Används till att få tag på hur många rader som ska existera i excel filen</param>
/// <returns></returns>
public string CreateExcel(List<Categories> categories)
{
Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
if (xlApp == null)
{
return "Excel är inte korrekt installerat";
}
Microsoft.Office.Interop.Excel.Workbook xlWorkBook;
Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;
xlWorkBook = xlApp.Workbooks.Add(misValue);
xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
categories1 = categories[0];
categories2 = categories[1];
categories3 = categories[2];
for(int i = 0; i < categories1.CategoryId.Count; i++)
{
if(categories1.NewCategoryId.Contains(categories1.CategoryId[i]) == false && categories1.CategoryId[i].Substring(3,4) == "0000")
{
categories1.NewCategoryId.Add(categories1.CategoryId[i]);
categories1.NewCategoryName.Add(categories1.CategoryName[i]);
}
}
Console.WriteLine(categories1.NewCategoryId.Count); 
for(int i = 0; i < ColumnNames.Count; i++)
{
xlWorkSheet.Cells[1, i + 1].Value2 = ColumnNames[i];
}
for(int i = 0; i < categories1.NewCategoryId.Count; i++)
{
xlWorkSheet.Cells[2 + i , 3].Value2 = categories1.NewCategoryName[i];
xlWorkSheet.Cells[2 + i, 4].Value2 = "Home";
}
for(int i = 0; i < categories2.CategoryId.Count; i++)
{
if(categories2.NewCategoryId.Contains(categories2.CategoryId[i]) == false && categories2.CategoryId[i].Substring(5, 2) == "00")
{
categories2.NewCategoryId.Add(categories2.CategoryId[i]);
categories2.NewCategoryName.Add(categories2.CategoryName[i]);
}
}
Console.WriteLine(categories2.NewCategoryName.Count); 
for(int i = 0; i < categories1.NewCategoryId.Count; i++)
{
for(int j = 0; j < categories2.NewCategoryId.Count; j++)
{
if(categories1.NewCategoryId[i].Substring(0,3) == categories2.NewCategoryId[j].Substring(0, 3))
{
categories2.parentCategoryId.Add(categories1.NewCategoryId[i]);
categories2.parentCategoryName.Add(categories1.NewCategoryName[i]);
} 
}
}
for(int i = 0; i < categories2.parentCategoryId.Count; i++)
{
xlWorkSheet.Cells[categories1.NewCategoryId.Count + i, 4].Value2 = categories2.parentCategoryName[i]; 
}
for(int i = 0; i < categories2.NewCategoryName.Count; i++)
{
xlWorkSheet.Cells[categories1.NewCategoryId.Count + i, 3].Value2 = categories2.NewCategoryName[i];
}
//Here saving the file in xlsx
xlWorkBook.SaveAs(@"C:UsersJens SvenssonDocuments" + name + ".xlsx", Microsoft.Office.Interop.Excel.XlFileFormat.xlOpenXMLWorkbook, misValue,
misValue, misValue, misValue, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
xlWorkBook.Close(true);
xlApp.Quit();
return "Funkar";
}
#endregion
private string createId(string Id, int start, int end)
{
return Id.Substring(start, end);
}
}
}

测试代码

public List<string> NewCategoryId = new List<string>();
public List<string> NewCategoryName = new List<string>();
public List<string> parentCategoryId = new List<string>();
public List<string> parentCategoryName = new List<string>();
parentCategoryId = <"3930000", "3930000",4230000, 5200000 >
parentCategoryName = <"Computers", "Computers", Toys, Furniture>
NewCategoryId = <"3931200", "4231400","5201300" "3931700">
NewCategoryName = <"Chairs","HP","ToyCars", "Lenovo">
for(int i = 0; i < NewCategoryId.Count; i++){
for(int j = 0; parentCategoryId.Count; j++){
if(parentCategoryId[j] == NewCategoryId[i]){
Console.Write(NewCategoryId[i] + "     ")
Console.Write(NewCategoryName[i] + "     ")
Console.Write(parentCategoryId[j] + "   " )
Console.Write(parentCategoryName[j] + "n")
}
}

}

Wanted result
3931700 Lenovo  3930000 Computers
3931200 HP      3930000 Computers
4231400 Chairs  4230000 Furniture
5201300 ToyCars 5201300 Toys

这是一个我不知道的结果，但我只是把它们弄乱了，所以怎么做呢？

Answer 1

我不太理解你的问题。我看了你的代码，它看起来很合理。

如果你愿意，你可以看看LinQ，特别是Where和Distinct扩展方法。

我希望我有用。

Answer 2

您可以使用.Intersect()检索匹配的元素，然后使用.IndexOf()获取索引。最后，访问其他列表的索引值。

var list1 = new List<int> { 1, 2, 3, 4, 5 };
var list2 = new List<int> { 4, 5, 6, 7, 8 };
var intersectingValues = list1.Intersect(list2); // 4, 5
var interesectingValueIndexes = intersectingValues.Select(x => 
new { I1 = list1.IndexOf(x), I2 = list2.IndexOf(x) });
var otherList1 = new List<string> { "a", "b", "c", "d", "e" };
var otherList2 = new List<string> { "f", "g", "h", "i", "j" };
var otherListIndexValues = interesectingValueIndexes.Select(x => 
new { V1 = otherList1[x.I1], V2 = otherList2[x.I2] });

Answer 3

您可以从其中一个列表创建Dictionary<T, int[]>，例如从list2:

using System.Linq;
...
var list1 = ...
var list2 = ... 
var dict = list2
.Select((value, index) => new {value, index})     
.GroupBy(pair => pair.value, pair => pair.index)
.ToDictionary(group => group.Key, group => group.ToArray());

现在，在dict.TryGetValue的帮助下，您可以获得list2中出现所需值的所有int[]索引，例如

foreach (var item in list1) {
if (dict.TryGetValue(item, out int[] indexes)) {
// item appears in list2 at indexes
Console.WriteLine($"value {item} appears at [{string.Join(", ", indexes)}]");
}
else {
// item is not found in list2 
}
}

演示：

var list1 = new List<string>() {"A", "B", "C", "D", "E"};
var list2 = new List<string>() {"A", "B", "A", "A", "C", "B", "D"};
var dict = list2
.Select((value, index) => new {value, index})     
.GroupBy(pair => pair.value, pair => pair.index)
.ToDictionary(group => group.Key, group => group.ToArray());
for (int i = 0; i < list1.Count; ++i) {
var item = list1[i];
if (dict.TryGetValue(item, out int[] indexes))
Console.WriteLine(
$"value {item} at {index} appears in list2 at [{string.Join(", ", indexes)}]");
else 
Console.WriteLine($"value {item} at {index} doesn't appear in list2");
}

结果：

value A at 0 appears in list2 at [0, 2, 3]
value B at 1 appears in list2 at [1, 5]
value C at 2 appears in list2 at [4]
value D at 3 appears in list2 at [6]
value E at 4 doesn't appear in list2