differences between StringBuilder in Java and C#

Question

I am converting Java code to C#. The StringBuilder class in Java seems to have many more methods than the C# one. I am interested in (say) the Java functionality

sb.indexOf(s);
sb.charAt(i);
sb.deleteCharAt(i);

which seems to be missing in C#.

I suppose the first two could be modelled by

sb.ToString().IndexOf(s);
sb.ToString().CharAt(i);

but would the third operate on a copy of the contents of the sb rather than the actual contents?

Is there a common way of adding this functionality to all missing methods?

Answer 1

You can use the Chars member collection for .charAt. Similarly, you can use .Remove(i,1) to remove a single char at position i.

Answer 2

For the third you could use the Remove method:

sb.Remove(i, 1);

Answer 3

You could use extension methods like the following:

    static class Extensions
    {
        public static int IndexOf(this StringBuilder sb, string value)
        {
            return sb.ToString().IndexOf(value);
        }

//if you must use CharAt instead of indexer
        public static int CharAt(this StringBuilder sb, int index)
        {
            return sb[index];
        }
    }

Answer 4

StringBuilder has an indexer, that means you can simply access single characters using sb[i]