Question

I want to find two or more variable in a string with Regex. For instance I have an string like this “Result = Num + 2 ( 6 * Count )”. I want to find out if “Result”, “Num” and “Count” are in this string or not. Suppose that I want to build a small compiler and these Strings are my reserved words and I want to use regex for this checks.

Case sensitive is more important for me. For example if client inputs “num” or “count” in a string, the method must return false.

How can I do it in C#?

Answer 1

Update to use arbitary word collection

var words = new [] { 
                     "Result",
                     "Num",
                     "Count"
                   };

var source = "Result = Num + 2 ( 6 * Count)";
var regex=new Regex(string.format(@"\b(?<words>(?-i){0})\b", string.Join("|",words));
var results = (
            from m in regex.Matches(source).OfType<Match>()
            select m.Groups["words"].Value
            ).ToArray();

results will be an array of matching words

However if as you state as your comment in another answer you are building a small compiler you would be better off building a tokenising engine. For example Build a Better Tokeniser