Replace Multiple String Elements in C#

Question

Is there a better way of doing this...

MyString .Trim().Replace("&", "and").Replace(",", "").Replace("  ", " ")
         .Replace(" ", "-").Replace("'", "").Replace("/", "").ToLower();

I've extended the string class to keep it down to one job but is there a quicker way?

public static class StringExtention
{
    public static string clean(this string s)
    {
        return s.Replace("&", "and").Replace(",", "").Replace("  ", " ")
                .Replace(" ", "-").Replace("'", "").Replace(".", "")
                .Replace("eacute;", "é").ToLower();
    }
}

Ta

Answer 1

Quicker - no. More effective - yes, if you will use the StringBuilder class. With your implementation each operation generates a copy of a string which under circumstances may impair performance. Strings are immutable objects so each operation just returns a modified copy.

If you expect this method to be actively called on multiple strings of significant length, it might be better to "migrate" its implementation onto the StringBuilder class. With it any modification is performed directly on that instance, so you spare unnecessary copy operations.

public static class StringExtention
{
    public static string clean(this string s)
    {
        StringBuilder sb = new StringBuilder (s);

        sb.Replace("&", "and");
        sb.Replace(",", "");
        sb.Replace("  ", " ");
        sb.Replace(" ", "-");
        sb.Replace("'", "");
        sb.Replace(".", "");
        sb.Replace("eacute;", "é");

        return sb.ToString().ToLower();
    }
}

Answer 2

this will be more effecient:

public static class StringExtention
{
    public static string clean(this string s)
    {
        return (new StringBuilder(s)).Replace("&", "and").Replace(",", "")
             .Replace("  ", " ").Replace(" ", "-").Replace("'", "")
             .Replace(".", "").Replace("eacute;", "é").ToString().ToLower();
    }
}

Answer 3

Maybe a little more readable?

    public static class StringExtension {

        private static Dictionary<string, string> _replacements = new Dictionary<string, string>();

        static StringExtension() {
            _replacements["&"] = "and";
            _replacements[","] = "";
            _replacements["  "] = " ";
            // etc...
        }

        public static string clean(this string s) {
            foreach (string to_replace in _replacements.Keys) {
                s = s.Replace(to_replace, _replacements[to_replace]);
            }
            return s;
        }
    }

Also add New In Town's suggestion about StringBuilder...

Answer 4

I think you should use Regular Expressions, RegExp object is the only fastest way to do what you are doing.

Regex reg = new Regex("(\&)|(\,)|(\W)|(eacute\;)", RegexOptions.IgnoreCase);
p = reg.Replace(p, 
(m)=>{  
   switch(m.ToString())
   {
      case "&":
         return "and";
      case "eacute;":
         return "é"; 
   }
   return "";
});