按从高到低的数字对列表（字符串）进行数字排序

Question

Context: I am designing a leader board and want to have the data displayed from the highest score to the lowest score. The problem being the data contains a string and integers which are imported from a text file. Currently I am able to sort the data numerically however I am using the OrderByDescending function which does not work. Eg 11,4,5,8,23,65 when ordered = 8,65,5,4,23,11 (sorted alphanumerically). The list contains the data: name(string), difficulty(string) and score(int) and I wish to sort the data in a descending order: Eg 1st = 10, 2nd = 9 etc.

List<string> leaderboardList = new List<string>();
StreamReader srUserData = new StreamReader(@"User Leaderboard.txt");
while ((userDataLine = srUserData.ReadLine()) != null)
        {
            leaderboardList.Add(userDataLine);
        }

leaderboardList = leaderboardList.OrderByDescending(x => Regex.Match(x, @"\d+").Value).ToList();

The Regex.Match finds the number in the string. Basically the final line is the line that needs amending. All help welcome, thanks.

Edit: The data should be outputted in the form Name, difficulty, score and sort the data in a descending order with the highest score.

Answer 1

Just change:

leaderboardList = leaderboardList.OrderByDescending(x =>
    Regex.Match(x, @"\d+").Value).ToList();

To:

leaderboardList = leaderboardList.OrderByDescending(x =>
    Int32.Parse(Regex.Match(x, @"\d+").Value)).ToList();

Just add the Int32.Parse really. A caveat though: If you pass a string that is not a number Int32.Parse() will throw an exception. If this is a possibility that needs to be handled, then you can use Int32.TryParse instead.

Ex:

int testValue = 0; //This is only used for TryParse()
leaderboardList = leaderboardList.OrderByDescending(x =>
        Int32.TryParse(Regex.Match(x, @"\d+").Value, out testValue)
        ? testValue : 0M).ToList();

Tested using the following example list:

List<string> leaderboardList = new List<string>();
leaderboardList.Add("Brandon|Easy|9");
leaderboardList.Add("Yoda|Impossible|9001");
leaderboardList.Add("Barney|Easy|-1");
leaderboardList.Add("John|Normal|500");

This code works correctly, and the TryParse code was not needed.

Output:

Yoda|Impossible|9001
John|Normal|500
Brandon|Easy|9
Barney|Easy|-1

Answer 2

I suggest a completely different approach from the others. Load your string from disk, then parse it into a class you have defined. For example:

public class LeaderboardRow
{
    public string Name { get; set; }
    public string Difficulty { get; set; }
    public int Score { get; set; }
}

Then your code would look more like this:

List<LeaderboardRow> leaderboardList = new List<LeaderboardRow>();
StreamReader srUserData = new StreamReader(@"User Leaderboard.txt");
while ((userDataLine = srUserData.ReadLine()) != null)
{
    //Put logic here that parses your string row into 3 distinct values
    leaderboardList.Add(new LeaderboardRow()
    {
        Score = 0, //put real value here
        Name = string.Empty, //put real value here
        Difficulty = string.Empty //put real value here
    });
}

Then any ordering you need to do is a simple LINQ statement:

leaderboardList = leaderboardList.OrderByDescending(x => x.Score).ToList();

Depending on your scenario/requirements you could store this text as json instead which could speed up and simplify your application.

Answer 3

You could go old school and perform Integer.TryParse or some derivative of such functions. Once you do that you can append them into a list of integers.

int number;
bool result = Int32.TryParse(value, out number);
if (result) {
Console.WriteLine("Converted '{0}' to {1}.", value, number);
}

Answer 4

You missed one thing, that is you are not convert Regex value to int. Please check below code, it's works for me.

CODE:

List<string> leaderboardList = new List<string>();
leaderboardList.Add("A,A,9");
leaderboardList.Add("B,B,8");
leaderboardList.Add("G,C,65");
leaderboardList.Add("S,B,10");

leaderboardList = leaderboardList.OrderByDescending(x =>Convert.ToInt32((string.IsNullOrEmpty(Regex.Match(x, @"\d+").Value)?"0":Regex.Match(x, @"\d+").Value))).ToList();
foreach (var item in leaderboardList)
{
    Console.WriteLine(item);
}

Online output: .Net Fiddle Output

Answer 5

You can use this for ordering list of numbers in string or list of string that contains numbers.

The Alphanum Algorithm

I hope this works for you.