Regex to return the word before the match

Question

I've been trying to extract the word before the match. For example, I have the following sentence:

"Allatoona was a town located in extreme southeastern Bartow County, Georgia."

I want to extract the word before "Bartow".

I've tried the following regex to extract that word:

\w\sCounty,

What I get returned is "w County" when what I wanted is just the word Bartow.

Any assistance would be greatly appreciated. Thanks!

Answer 1

You can use this regex with a lookahead to find word before County:

\w+(?=\s+County)

(?=\s+County) is a positive lookahead that asserts presence of 1 or more whitespaces followed by word County ahead of current match.

RegEx Demo

If you want to avoid lookahead then you can use a capture group:

(\w+)\s+County

and extract captured group #1 from match result.

Answer 2

Your \w\sCounty, regex returns w County because \w matches a single character that is either a letter, digit, or _. It does not match a whole word.

To match 1 or more symbols, you need to use a + quantifier and to capture the part you need to extract you can rely on capturing groups, (...).

So, you can fix your pattern by mere replacing \w with (\w+) and then, after getting a match, access the Match.Groups[1].Value.

However, if the county name contains a non-word symbol, like a hyphen, \w+ won't match it. A \S+ matching 1 or more non-whitespace symbols might turn out a better option in that case.

See a C# demo:

var m = Regex.Match(s, @"(\S+)\s+County");
if (m.Success) 
{
     Console.WriteLine(m.Groups[1].Value);  
}

See a regex demo.