Question

I’m developing a simple little search mechanism and I want to allow the user to search for chunks of text with spaces. For example, a user can search for the name of a person:

Name: John Smith

I then "John Smith".Split(' ') into an array of two elements, {"John","Smith"}. I then return all of the records that match “John” AND “Smith” first followed by records that match either "John" OR "Smith." I then return no records for no matches. This isn’t a complicated scenario and I have this part working.

I’d now like to be able to allow the user to ONLY return records that match “John Smith”

I’d like to use a basic quote syntax for searching. So if a user wants to search for “John Smith” OR Pocahontas they would enter: “John Smith” Pocahontas. The order of terms is absolutely irrelevant; “John Smith” does not receive priority over Pocahontas because he comes first in the list.

I have two main trains of thought on how I should parse the input.

A) Using regular expression then parsing stuff (IndexOf, Split)
B) Using only the parsing methods 

I think a logical point of action would be to find the stuff in quotes; then remove it from the original string and insert it into a separate list. Then all the stuff left over from the original string could be split on the space and inserted into that separate list. If there is either 1 quote or an odd number, it is simply removed from the list.

How do I find matches the from within regex? I know about regex.Replace, but how would I iterate through the matches and insert them into a list. I know there is some neat way to do this using the MatchEvaluator delegate and linq, but I know basically nothing about regex in c#.

Answer 1

Use a regex like this:

string input = "\"John Smith\" Pocahontas";
Regex rx = new Regex(@"(?<="")[^""]+(?="")|[^\s""]\S*");
for (Match match = rx.Match(input); match.Success; match = match.NextMatch()) {
    // use match.Value here, it contains the string to be searched
}