I have some .txt files.

The first line of text in each of the files is a number.

I can get a list of all the file names by doing the following:

DirectoryInfo di = new DirectoryInfo(filePath);
FileInfo[] files = di.GetFiles("*.txt");
string[] fileNames = new string[files.Length];

for (int i = 0; i < files.Length; i  )
{
    fileNames[i] = files[i].Name;
}
return fileNames.ToList();

I need to sort the list names based on the number in these files. From lowest to highest.

There are no duplicate, negative, or decimal numbers (so only positive integers).

Also, you can get the number in the files by doing the following:

foreach (string name in names)
{
    string[] lines = File.ReadAllLines(filePath   name);
    int number = Convert.ToInt32(lines[0]);
}

How do I do this?

CodePudding user response：

You can use the jagged Array for this.

string[][] arr = new string[names.Length][];

for (int i = 0; i < arr.Length; i  )
{
    string[] lines = File.ReadAllLines(filePath   names[i]   ".txt");
    arr[i] = new string[] { lines[0], names[i]};
}

and then make a list using any sorting method while accessing the first element of each array by arr[j][0]. Here j is a variable used to move through the array.

CodePudding user response：

I would go like this -- see comments inline

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

public class FileMeta
{
    public string Name {get; set;}

    public string Path {get; set;}
    
    public int Index {get; set;}
    

}


public class Program
{
    public static void Main()
    {
        string dirPath = Path.Combine("c:", "dir1", "dir2");  // USE Path combine, not concatenation
        IEnumerable<FileMeta> metaList = Directory.EnumerateFiles(dirPath, "*.txt", SearchOption.AllDirectories) // USE LINQ to retrieve file path
            .Select(file =>
            {
                int index = 0;
                string fName = Path.GetFileName(file);
                string line = File.ReadLines(file).FirstOrDefault(); // Get a line if exists
                if (!string.IsNullOrWhiteSpace(line))
                    int.TryParse(line.Trim(), out index); // Don't care if parse or not. If not - default 0
                
                
                return new FileMeta(){Name = fName, Path = file, Index = index};
                
            })
            .OrderBy(meta => meta.Index);
        
        // PRINT
        foreach (var meta in metaList)
        {
            Console.WriteLine(@"Full file name: {0}
Name: {1}
Index: {2}", meta.Path, meta.Name, meta.Index);
        }
        
    }
    
    
}

Disclaimer:

• not tested

• Done in .net 6

• Error handling not provided

CodePudding user response：

string[] names = Directory.GetDirectories(filePath).Select(Path.GetFileName).ToArray();
string temp=null;
for(int i=0; i<=names.size(); i  )
 {
 for(int j=i 1; j<=names.size(); j  )
 {
   string[] lines1 = File.ReadAllLines(filePath   names[i]   ".txt");
   int number1 = Convert.ToInt32(lines1[0]);
   string[] lines2 = File.ReadAllLines(filePath   names[j]   ".txt");
   int number2 = Convert.ToInt32(lines2[0]);
   if(number1>number2)
    {
                             
     temp=num[i];
     names[i]=names[j];
     names[j]=temp;
    }
 }
           
}