如何从字符串中删除干扰词并使用RegEx搜索？ C＃

Question

I am trying to perform a search for a string within a string.

StringToSearch: The quick brown fox jumped over the fence
searchTerm: brown jumped

so when i do a StringToSearch.ContainsEx(searchTerm) it returns true. So the way I have it working now is, I first remove nosie words using string.Remove() then do a string.Split(' ') to get the words and then perform a contains search on all words from this array in the text to be searched.

It works but I want it to make as performant as I can, so can I make use of RegEx to do the same kind of search? ie 1) Remove noise words like the , of etc and then see if all words in the searchString are contained within the text to be searched?

I have no idea on uisng RegEx's in C# at all so code sample would be helpful. Thank you and please suggest any other techniques if you feel that they will serve me better than Regular expressions.

Answer 1

Try this(If you need, add more words like similar fashion):

string sPattern = "(?=.*\bbrown\b)(?=.*\bjumped\b)"
if (System.Text.RegularExpressions.Regex.IsMatch(mainString, sPattern))
{
    // do something
}

(?=.*\\bbrown\\b) = Using positive lookahead it is checking if the word brown exists in the text. \\b is word boundary, so that it doesn't pick the word from another. For example avoiding and from the word land

Answer 2

Try using Linq , I think it will be good if both of your strings are long. Using regex you first have to contruct a regex dynamically (for each element of searchTerm) and you would end up with a long regex, that might be slow.

List<string> StringToSearchList = new List<string>(StringToSearch.Split(' '));
List<string> searchTermList = new List<string>(searchTerm.Split(' '));

var query = StringToSearchList.Select(c => c).Except(searchTermList);

You can use string.Join to convert array to a string .