How to parse this?

Question

I need to parse out the string that has following structure

x:{a,b,c,}, y:{d,e,f} etc.

where all entries are numbers so it would look something like this

411:{1,2,3},241:{4,1,2} etc.

Forgot to mention: number of comma delimited entries in between {} has no upper limit but has to have at least one entry.

1. I need to get the unique list of the numbers before :, in above case 411,241

Can this be done with regex and how?

Answer 1

I think this might work, Pseudo-Code

foreach match in Regex.Matches(yourInputString, "[0-9]{3}:\{[0-9,]\},")
    firstNumber = match.Value.Substring(0, 3)
    numbers() = match.Value.Substring(4, match.Value.Length - 5).Split(",")
next

Bobby

Answer 2

Why do you want to do this with regex? I mean, you're querying the string for id's and given an id, want to retrieve it's values. I'd just break the string up and create a map structure that has the id as key, and a collection of numbers as their values.

Answer 3

Regex:

(?<1>[\d]+):{(?<2>\d+),(?<3>\d+),(?<4>\d+)}

For data:

411:{1,2,3},241:{4,1,2},314:{5,6,7}

will produce the following match/groups collections:

Match 0
Group 0: 411:{1,2,3}
Group 1: 411
Group 2: 1
Group 3: 2
Group 4: 3

Match 1
Group 0: 241:{4,1,2}
Group 1: 241
Group 2: 4
Group 3: 1
Group 4: 2

Match 2
Group 0: 314:{5,6,7}
Group 1: 314
Group 2: 5
Group 3: 6
Group 4: 7

You can use the following code:

string expression = "(?<1>[\d]*):{(?<2>\d),(?<3>\d),(?<4>\d)}";
string input = "411:{1,2,3},241:{4,1,2},314:{5,6,7}";

Regex re = new Regex(expression, RegexOptions.IgnoreCase);

MatchCollection matches = re.Matches(input);

for (int i = 0; i < matches.Count; i++)
{
Match m = matches[i];
// for i==0
// m.groups[0] == 411:{1,2,3}
// m.groups[1] == 411
// m.groups[2] == 1
// m.groups[3] == 2
// m.groups[4] == 4
}

Update Having trouble getting it to work with pure regex and variable number of items in the list - maybe someone else can chime in here. A simple solution would be:

string expression = "(?<1>[\d]+):{(?<2>[\d,?]+)}";
string input = "411:{1,2,3,4,5},241:{4,1,234}";

Regex re = new Regex(expression, RegexOptions.IgnoreCase);

MatchCollection matches = re.Matches(input);

for (int i = 0; i < matches.Count; i++)
{
Match m = matches[i];
// for i==0
// m.groups[0] == "411:{1,2,3}"
// m.groups[1] == "411"
// m.groups[2] == "1,2,3"
int[] list = m.Groups[1].Split(",");
// now list is an array of what was between the curly braces for this match
}

Match list for above:

Match 0
Group 0: 411:{1,2,3,4,5}
Group 1: 411
Group 2: 1,2,3,4,5

Match 1
Group 0: 241:{4,1,234}
Group 1: 241
Group 2: 4,1,234

Answer 4

The first one is achievable with the following regex:

\d*(?=:)

Answer 5

If we consider x:{a,b,c} an element, the following would give you a list of matches with two named grounps: Outer and Inner. Outer being x, Inner being a,b,c.

(?<outer>\d+):\{(?<inner>\d+(,\d+)*)\}

Update

Here is a code sample:

        String input = "411:{1,2,3},241:{4,1,2},45:{1},34:{1,34,234}";
        String expr = @"(?<outer>\d+):\{(?<inner>\d+(,\d+)*)\}";

        MatchCollection matches = Regex.Matches(input, expr);

        foreach (Match match in matches)
        {
            Console.WriteLine("Outer: {0} Inner: {1}", match.Groups["outer"].Value, match.Groups["inner"]);
        }

Answer 6

this string have the json format. so you can use Json.Net to parse it for you

Answer 7

Are you working with JSON? If so, you might want to check out the JavaScriptSerializer Class on MSDN,

http://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer.aspx

Answer 8

Here's an alternative without RegEx that will run faster.

This returns a Dictionary<Double, List<Double>>....

public Dictionary<double, List<double>> Example()
        {
            String[] aSeparators = {"{", "},", ",", "}"};
            String data = "411:{1,2,3},843:{6,5,4,3,2,1},241:{4,1,2}";
            String[] bases = data.Split(aSeparators, StringSplitOptions.RemoveEmptyEntries);
            Dictionary<double, List<double>> aDict = null;

            double aHeadValue = 0;
            List<Double> aList = null;
            foreach (var value in bases)
            {
                if (value.EndsWith(":"))
                {
                    if (aDict == null)
                        aDict = new Dictionary<double, List<double>>();
                    else
                        aDict.Add(aHeadValue, aList);
                    aHeadValue = Double.Parse(value.TrimEnd(':'));
                    aList = new List<Double>();
                }
                else
                {
                    aList.Add(Double.Parse(value));
                }
            }
            aDict.Add(aHeadValue, aList);
            return aDict;
        }