title: Replace single character in a String
body: <p>So, I'm using unity and I have this string that contains the current state of a tic-tac-toe board. It looks like that:</p>
  
  <pre><code>XOX
  ONX
  OXX
  </code></pre>
  
  <p>"N" being a neutral space.</p>
  
  <p>The thing is I want to replace one of those "N" with either an "X" or an "O".
  I tried using :</p>
  
  <pre><code>board[n] = "X";
  </code></pre>
  
  <p>but i get </p>
  
  <blockquote>
    <p>"property or indexer cannot be assigned, it is read only"</p>
  </blockquote>
  
  <p>So I'm trying to figure a way to change one of those "N". Here is my code</p>
  
  <pre><code>if (manager.turn == 1 &amp;&amp; !isUsed)
  {
      xSprite.enabled = true;
      manager.board[int.Parse(gameObject.name)-1] = 'X';
      manager.GameEndingDraw();
      isUsed = true;
      manager.turn = 2;
  }
  else if (manager.turn == 2 &amp;&amp; !isUsed)
  {
      oSprite.enabled = true;
      manager.board[int.Parse(gameObject.name)-1] = 'O';
      manager.GameEndingDraw();
      isUsed = true;
      manager.turn = 1;
  }
  </code></pre>