Regular Expression for parsing ASCII data

Question

Right now I have a couple separate regular expressions to filter data from a string but I'm curious if there's a way to do it all in one go.

Sample Data: (DATA$0$34.0002,5.3114$34.0002,5.2925$34.0004,5.3214$34.0007,2.2527$34.0002,44.3604$34.0002,43.689$34.0004,38.3179$34.0007,8.1299)

Need to verify there's an open and close parentheses ( )
Need to verify there's a "DATA$0" after the open parenthesis
Need to split the results by $
Need to split that subset by comma
Need to capture only the last item of that subset (i.e. 5.3114, 5.2925, 5.3214, etc.)

My first check is on parenthesis using (([^)]+)) as my RegEx w/ RightToLeft & ExplicitCapture options (some lines can have multiple data sets).

Next I filter for the DATA$0 using (?:(DATA$0)

Finally I do my splits and take the last value in the array to get what I need but I'm trying to figure out if there's a better way.

string DataPattern = @"(?:\(DATA\$0)";
string ParenthesisPattern = @"\(([^)]+)\)";
RegexOptions options = RegexOptions.RightToLeft | RegexOptions.ExplicitCapture;

StreamReader sr = new StreamReader(FilePath);
while (!sr.EndOfStream)
{
    string line = sr.ReadLine();
    Console.WriteLine(line);

    Match parentMatch = Regex.Match(line, ParenthesisPattern, options);
    if (parentMatch.Success)
    {
        string value = parentMatch.Value;

        Match dataMatch = Regex.Match(value, DataPattern);
        if (dataMatch.Success)
        {
            string output = parentMatch.Value.Replace("(DATA$0", "").Replace(")", "");
            string[] splitOutput = Regex.Split(output, @"\$");

            foreach (string x in splitOutput)
            {
                if (!string.IsNullOrEmpty(x))
                {
                    string[] splitDollar = Regex.Split(x, ",");
                    if (splitDollar.Length > 0)
                        Console.WriteLine("Value: " + splitDollar[splitDollar.Length - 1]);
                }
            }
        }
        else
            Console.WriteLine("NO DATA");
    }
    else
        Console.WriteLine("NO PARENTHESIS");

    Console.ReadLine();
}

TIA

Wiktor Stribiżew · Accepted Answer · 2022-05-06 21:57:43Z

1

You can use

var results = Regex.Matches(text, @"(?<=\(DATA\$0[^()]*,)[^(),$]+(?=(?:\$[^()]*)?\))")
    .Cast<Match>()
    .Select(x => x.Value)
    .ToList();

See the regex demo. Details:

(?<=\(DATA\$0[^()]*,) - a positive lookbehind that matches a location that is immediately preceded with (DATA$0, zero or more chars other than ( and ) (as many as possible) and a comma
[^(),$]+ - one or more chars other than (, ), $ and a comma
(?=(?:\$[^()]*)?\)) - the current location must be immediately followed with an optional occurrence of a $ char and then zero or more chars other than ( and ), and then a ) char.

An alternative:

var results = Regex.Matches(text, @"(?:\G(?!^)|\(DATA\$0)[^()]*?,([^(),$]+)(?=(?:\$[^()]*)?\))")
    .Cast<Match>()
    .Select(x => x.Groups[1].Value)
    .ToList();

See the regex demo. Details:

(?:\G(?!^)|\(DATA\$0) - either the end of the previous successful match, or (DATA$0 string
[^()]*? - zero or more chars other than (, ), ,, as few as possible
, - a comma
([^(),$]+) - Group 1: one or more chars other than (, ), ,, $
(?=(?:\$[^()]*)?\)) - a positive lookahead matching the location that is immediately followed with an optional occurrence of a $ char followed with zero or more chars other than ( and ), and then a ) char.

edited May 6, 2022 at 21:57

answered May 6, 2022 at 17:05

Wiktor Stribiżew

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2 Comments

BBousman Over a year ago

Okay, that works for the 1 sample data I sent above but I found out the data that we're receiving can actually have different numbers of values between $ per line: (DATA$0$24.0001,5.3038,26.0001,5.3055,28,5.3078$24.0002,5.2921,26,5.2965,28.0001,5.2914$24.0003,5.3183,26.0002,5.327,28.0002,5.3176$24.0004,2.2584,26.0002,2.2686,28.0003,2.2594$24.0001,44.7754,26.0001,45.7031,28,45.9595$24.0002,43.6157,26,44.3848,28.0001,43.9697$24.0003,42.4561,26.0002,37.7686,28.0002,38.0493$24.0004,9.082,26.0002,7.9468,28.0003,8.0566)

Wiktor Stribiżew Over a year ago

@BBousman Please check the two solutions now.

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