Regular Expression to replace non alpha characters with spaces

Question

I have been trying to build a regular expression but haven\'t been able to get one specific condition to work.

I want a regex to remove all non alpha characters with the

Answer 1

// Skip over '-', grab non-word characters or the ' -' sequence to replace
string pattern = @"(?!-)(\W| -)+";  
string replacement = "";
Regex regex = new Regex(pattern);
string result = regex .Replace("Replace - this *@#&@#* string-already", replacement);

The (?!-) is a zero-width negative lookahead assertion that will skip over the '-' symbol... the second group will match it if it's preceded by a space.

If you're trying to substitute a space instead of completely removing the characters, just change to

string replacement = " ";

the pattern is greedy, so it will replace groups of non-word characters with a single space.