C# convert formatted string (31.2k) back to number (31240)

Question

Let's say I have this code:

int i = 31240;
string Number = ((double)i / 1000).ToString("0.#k");

I get this result as a string for Number: 31,2k

And now, I wanna do the exact opposite, that is to take this string "31,2k" and take it back to 31240 or even to 31200, but I don't know how to do... Any idea?

---

Someone said that was impossible. BUT Finally I found the perfect way to achieve my goal. I post the solution for those who could be willing to know. The use is simple, and it allows to make 2 kind of conversions:

• Thousands, Example: 45831 <=> 45,8k <=> 45831
• Millions, Example: 123852376 <=> 123,5m <=> 123852376

Answer 1

Here is the solution I went through:

public class StringFromInt
{
    public enum FormatStyle
    {
        Kilo = 1000,
        Mega = 1000000
    }
    public int Number;
    public FormatStyle Format
    {
        get
        {
            switch (LimitValueBeforeConversion)
            {
                case 1000: return FormatStyle.Kilo;
                case 1000000: return FormatStyle.Mega;
                default:
                    throw new NotImplementedException("You must implement the code for this kind of value");
            }
        }
        set
        {
            if (value == FormatStyle.Kilo)
            {
                LimitValueBeforeConversion = 1000;
            }
            else if (value == FormatStyle.Mega)
            {
                LimitValueBeforeConversion = 1000000;
            }
        }
    }
    public int LimitValueBeforeConversion
    { get; set; }
    public static implicit operator int(StringFromInt s)
    {
        return s.Number;
    }
    public static implicit operator StringFromInt(int number)
    {
        StringFromInt s = new StringFromInt(number);
        return s;
    }

    #region Constructors
    public StringFromInt(int number, FormatStyle format)
    {
        this.Number = number;
        Format = format;
    }
    public StringFromInt(int number)
        : this(number, FormatStyle.Kilo)
    {
        if (number >= 1000000)
        {
            this.Format = FormatStyle.Mega;
        }
    }
    #endregion

    public override string ToString()
    {
        if (Number >= LimitValueBeforeConversion)
        {
            string formatString = "0.#k";
            switch (Format)
            {
                case FormatStyle.Kilo:
                    formatString = "0.#k";
                    break;
                case FormatStyle.Mega:
                    formatString = "0.#m";
                    break;
                default:
                    throw new NotImplementedException("You must implement the code for this kind of value");
            }
            return ((double)Number / LimitValueBeforeConversion).ToString(formatString);
        }
        else
        {
            return Number.ToString();
        }
    }
}

---

And here is a test program:

class Program
{
    static void Main(string[] args)
    {
        int i = 31240;

        string StringRepresentation = ((double)i / 1000).ToString("0.#k");
        int resultBackWithParse = int.Parse(StringRepresentation.Substring(0, StringRepresentation.Length - 1).Replace(CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator, string.Empty)) * 100;
        Console.WriteLine("Base number: " + i.ToString());
        Console.WriteLine(new string('-', 35));
        Console.WriteLine("String representation: " + StringRepresentation);
        Console.WriteLine("Int representation With Int.Parse: " + resultBackWithParse.ToString());
        Console.WriteLine();
        StringFromInt MySolutionNumber = i;
        int resultBackWithStringFromInt = MySolutionNumber;
        Console.WriteLine("String representation With StringFromInt: " + MySolutionNumber.ToString());
        Console.WriteLine("Int representation With StringFromInt: " + resultBackWithStringFromInt);

        Console.WriteLine(new string('=', 35) + "\n");
        i = 123456789;
        StringFromInt MyNumber = 123456789;
        int resultBack = MyNumber;
        Console.WriteLine("Base number: " + i.ToString());
        Console.WriteLine(new string('-', 35));
        Console.WriteLine("String representation With StringFromInt: " + MyNumber);
        Console.WriteLine("Int representation With StringFromInt: " + resultBack);

        Console.ReadKey(true);
    }
}

---

As you can notice, there is no need to use the "new" initializer, I mean no need to do:

StringFromInt Number = new StringFromInt(YourNumber)

Thanks to the implicit operator, you can do:

StringFromInt Number = YourNumber

I don't know, but I think it's a good beginning, what do you think?

Anyway, I managed to do what I wanted, so for people who thought it couldn't be done, you see, that's possible :-)

Obviously this can be improved: this version works for thousands and millions only.

Greetings