Find exact match of string and the matching position

Question

I want to search keyword stored in variable kw in large length text and find the FIRST position at which keyword is found . Below code doesn't do EXACT keyword match .

if (webData.IndexOf(kw, StringComparison.OrdinalIgnoreCase) != -1)
{
     found = true;
     int pos = webData.IndexOf(kw, StringComparison.OrdinalIgnoreCase); 
}

how to do it using regex ?

Match match = Regex.Match(webData, @"^kw$", RegexOptions.IgnoreCase);

if (match.Success)
{
  int pos = //Matching position
}

Answer 1

You can do

Match match = Regex.Match(webData, @"\b"+Regex.Escape(kw)+@"\b", RegexOptions.IgnoreCase);

if (match.Success)
{
  int pos = match.Index;
}

For exact match you need to use boundary represented by \\b

More info here

Answer 2

The Match will have an Index property doing just what you want:

Match match = Regex.Match(webData, pattern, RegexOptions.IgnoreCase);

if (match.Success)
{
  int pos = match.Index;
}

Index - The position in the original string where the first character of the captured substring is found. (Inherited from Capture.)