How to change all subscript characters in a string to normal in C#?

Question

I have a problem regarding subscript characters in a string. Lets say i have the following string: O₂.

I want all subscribt characters of that string to be normal so the string will look like: O2.(and not O₂)

I am not sure how to do that i C#.

Answer 1

There is a general "decomposition" of all superscript and subscript characters in .NET, as described here: How to convert super- or subscript to normal text in C#.

However, if you want to do stuff manually, and if you want just the numbers 0-9 in subscript, they can be found at U+2080 - U+2089 (http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts).

So, you could use the C# string representation of unicode characters, \uXXXX, and the int value of '0' to help you.

The difference in character "numeric" values of the subscript of a number and the number in plain writing, would be:

(int) '\u2080' - (int) '0'

Putting it together, the following will probably explain it better:

using System.IO; using System;

class Program
{
    static void Main()
    {
       var subscriptValue = (int) '\u2080';
       var normalValue = (int) '0';
       var diff = subscriptValue - normalValue;
       Console.WriteLine("subscript value: {0}, normal value: {1}, difference: {2} ",
            subscriptValue, normalValue, diff);

       for (var i = normalValue; i <= (normalValue + 9); i++) {
           char normal = (char) i;
           char subscript = (char) (i + diff);
           Console.WriteLine("Normal: {0}, subscript: {1}", normal, subscript);
       }

    }
}

Answer 2

If you want to convert standard unicode subscript block ([0x2080..0x209F] symbols) you may use this code:

http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts

    /// <summary>
    /// From subscript (standard subscript block [0x2080..0x209F] only) to normal
    /// </summary>
    public static String FromSubscript(String value) {
      if (String.IsNullOrEmpty(value))
        return value;

      Char[] Symbols = new Char[] { 
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '-', '=', '(', ')', '?',  // <- '?' unknown/not standard symbols
        'a', 'e', 'o', 'x', '\u0259', 'h', 'k', 'l', 'm', 'n', 'p', 's', 't', '?', '?', '?' }; // <- u0259 - small latin shwa

      StringBuilder result = new StringBuilder(value.Length);

      foreach (Char ch in value) {
        int v = (int) ch;

        if ((v >= 0x2080) && (v <= 0x209F))
          result.Append(Symbols[v - 0x2080]);
        else
          result.Append(ch);
      }

      return result.ToString();
    }

  ... 

  String test = "O₂";

  Debug.Assert(String.Equals(FromSubscript(test), "O2", StringComparison.Ordinal));