A faster way of doing multiple string replacements

Question

I need to do the following:

    static string[] pats = { "å", "Å", "æ", "Æ", "ä", "Ä", "ö", "Ö", "ø", "Ø" ,"è", "È", "à", "À", "ì", "Ì", "õ", "Õ", "ï", "Ï" };     static string[] repl = { "a", "A", "a", "A", "a", "A", "o", "O", "o", "O", "e", "E", "a", "A", "i", "I", "o", "O", "i", "I" };     static int i = pats.Length;     int j;       // function for the replacement(s)      public string DoRepl(string Inp) {       string tmp = Inp;         for( j = 0; j < i; j++ ) {             tmp = Regex.Replace(tmp,pats[j],repl[j]);         }         return tmp.ToString();                 }     /* Main flow processes about 45000 lines of input */ 

Each line has 6 elements that go through DoRepl. Approximately 300,000 function calls. Each does 20 Regex.Replace, totalling ~6 million replaces.

Is there any more elegant way to do this in fewer passes?

Answer 1

static Dictionary<char, char> repl = new Dictionary<char, char>() { { 'å', 'a' }, { 'ø', 'o' } }; // etc... public string DoRepl(string Inp) {     var tmp = Inp.Select(c =>     {         char r;         if (repl.TryGetValue(c, out r))             return r;         return c;     });     return new string(tmp.ToArray()); } 

Each char is checked only once against a dictionary and replaced if found in the dictionary.

Answer 2

How about this "trick"?

string conv = Encoding.ASCII.GetString(Encoding.GetEncoding("Cyrillic").GetBytes(input));