Question

I need to escape these characters: +-&|!(){}[]^"~*?:\ by preceding them with a \\.
What is the best way to do this. My first thought was using replace, but that would search the string for each item to replace.
I’m thinking there must be a way to do it with regular expressions that would get all in one pass.

Answer 1

It’s possible with a regular expression. The trickiest part is correctly escaping the special characters without getting into backslash hell:

s = Regex.Replace(s, @"[+\-&|!(){}[\]^""~*?:\\]", "\\$0");

The StringBuilder solution mentioned by Eric J. is simple and quite elegant. Here’s one way to code it:

StringBuilder sb = new StringBuilder();
foreach (char c in s)
{
    if ("+-&|!(){}[]^\"~*?:\\".Contains(c))
    {
        sb.Append('\\');
    }
    sb.Append(c);
}
s = sb.ToString();