filtering values from string after/before certain word in c#

Question

I have quite long strings, which are response from IMAP request, and I want to extract some values from it. It's usually formatted like "x someword" or "someword x" - how get x (it can be more than one digit) for someword (which is known) ? Each "line" of response looks like:

* x someword \r\n

and my string contain a couple of this lines. What's the simplest way to extract desired values?

Example: for "* x word1\r\n* y word2\r\n", with word2 as a parameter I want to get y

Whole response example:

* FLAGS (\\Answered \\Flagged \\Draft \\Deleted \\Seen)\r\n* OK [PERMANENTFLAGS ()] Flags permitted.\r\n* OK [UIDVALIDITY xxx] UIDs valid.\r\n* 3 EXISTS\r\n* 0 RECENT\r\n* OK [UIDNEXT x] Predicted next UID.\r\n. OK [READ-ONLY] INBOX selected. (Success)\r\n

For "EXISTS" I want to get 3.

Answer 1

I would use Regular Expressions... here's what you can do:

string myString = "* FLAGS (\\Answered \\Flagged \\Draft \\Deleted \\Seen)\r\n* OK [PERMANENTFLAGS ()] Flags permitted.\r\n* OK [UIDVALIDITY 657136382] UIDs valid.\r\n* 3 EXISTS\r\n* 0 RECENT\r\n* OK [UIDNEXT 4] Predicted next UID.\r\n. OK [READ-ONLY] INBOX selected. (Success)\r\n";

string myWordToFind = "EXISTS";

string result = Regex.Match(myString, @"(?<MyNumber>\d+)\s*(" + Regex.Escape(myWordToFind) + ")",
    RegexOptions.Compiled | RegexOptions.IgnoreCase)
    .Groups["MyNumber"].Value;

Answer 2

So given: X markerWord\n\rmarkerWord Y

you want {X, Y}? If so, try to split by lines first, and then simply remove "markerWord".

Something roughly like:

var result = input.Split(new[]{'\n', '\r'}).Select(line => line.Replace("markerWord", string.Empty);

Updated answer: Well then I would use Regex. Simple proof of concept, I'm sure you can take it from here:

static string GetParam(string input, string param) {
            var pattern = new Regex(@"[\\*](?<value>.+)" + param);
            var split = input.Split(new[] { '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries);
            var line = split.SingleOrDefault(l => pattern.IsMatch(l));
            if(line != null) {
                return pattern.Match(line).Groups["value"].Value.Trim();
            }
            return null;
        }