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C# and Regex: How to extract strings between quotation marks

Answer 1

A:

I think you need to remove the " at the beginning and the end and split by ","

string [] test=Regex.Split(s.SubString(1,s.length-2), "\",\"");

weismat 2009-05-22 08:06:23

Answer 2

A:

Try the following:

using System.Text.RegularExpressions;

public static MatchCollection getMatches(String input, String pattern) {
   Regex re = new Regex(pattern);
   return re.Matches(input);
}

public static void Example() {
   String pattern1 = "var matches = new Array\\(([^\\)]+)\\)";

   MatchCollection results = getMatches(RandomTest, pattern1);
   String marray = results[0].Groups[1].Value;

   String pattern2 = "\"([^\"]+)\"";
   List<String> values = new List<String>();
   foreach (Match value in getMatches(marray,pattern2)) {
      //Your values are in the Groups property
      values.Add(value.Groups[1].Value);
      Console.WriteLine(value.Groups[1].Value);
   }
}

The first pattern extracts the matches array and the second grabs all the quoted values in that array

RobV 2009-05-22 08:21:12

Answer 3

+1 A:

Please don't use regular expressions for this, CSV should be handled by a parser. Doing this with regex is the slowest and most error-prone method of all.

Here is a ready-to-use parser: codeproject.com: A Fast CSV Reader. Others examples can easily be found, as implementing a CSV parser is a popular excercise.

You can also use the OLEDB built-in parser: C# Tutorial - Using The Built In OLEDB CSV Parser.

With your example, I would use IndexOf() to cut out the string between "var matches = new Array(" and ");", and treat the result as a CSV string.

Tomalak 2009-05-22 08:25:55

To be fair, most parser generators I've came across use regular expressions to define the grammar.

DrJokepu 2009-05-22 08:59:56

@DrJokepu: It’s not impossible to parse CSV data with regular expressions. But it’s not the most efficient way. Time consumption of regular expressions can be exponential O(n^c) (due to backtracking) while a parser has just O(n). (I hope the estimates are correct.)

Gumbo 2009-05-22 09:18:50

Answer 4

+1 A:

I would use the following Regex pattern to match the entire Array contents :

"var matches = new Array\(\s+(.*?)\s+\)"

... and then perform a String.Split on the comma separator.

Cerebrus 2009-05-22 08:26:14

Answer 5

A:

If you really want to use regular expressions, try something like this:

var matches = new Array\(\s*("(?:[^\\"]*|\\.)*"\s*(?:,\s*"(?:[^\\"]*|\\.)*")*)\s*\);

That should get you the array value list. Then another regular expression can get you the single values:

"(?:[^\\"]*|\\.)*"

But again: Using regular expressions in this case is not that efficient. A simple CSV parser will be way better.

Gumbo 2009-05-22 08:56:42

Answer 6

A:

If you need a single list for all the lines together use this:

/// <returns>Returns all values inside matches array in a single list</returns>
        public static List<string> GetMatchesArray(String inputString)
        {
            // Matches var matches = new Array( ... );
            Regex r = new Regex("(var matches = new Array\\([^\\)]*\\);)",
                RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Multiline);

            string arrayString = r.Match(inputString).Groups[0].Value;

            List<string> quotedList = new List<string>();

            // Matches all the data between the quotes inside var matches
            r = new Regex("\"([^\"]+)\"", RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Multiline);
            for (Match m = r.Match(arrayString); m.Success; m = m.NextMatch())
            {
                quotedList.Add(m.Groups[1].Value);
            }

            return quotedList;
        }

If you want to have a separate list per line, you should have a list of lines, and within each list you should have a list of quoted text. The code below will do that:

/// This will help you store the data in a list in a more meaningful way, 
/// so that you are able to organize the data per line
/// Returns all the quoted text per line in a list of lines
public static List<List<string>> GetMatchesArrayPerLine(String inputString)
{
    // Matches var matches = new Array( ... )
    Regex r = new Regex("(var matches = new Array\\([^\\)]*\\);)",
        RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Multiline);

    string arrayString = r.Match(inputString).Groups[0].Value;

    List<string> lineList = new List<string>();

    // Matches all the lines and stores them in lineList one line per item. For e.g.
    // "125","1.FC Nurnberg - TSV 1860 Munich", ...
    // "126","FC Ingolstadt 04 - TuS Koblenz", ...
    r = new Regex("\n(.*)", RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Multiline);
    for (Match m = r.Match(arrayString); m.Success; m = m.NextMatch())
    {
        lineList.Add(m.Groups[1].Value);
    }

    List<List<string>> quotedListPerLine = new List<List<string>>();

    // Matches the quoted text per line. 
    // This will help you store data in an organised way rather than just a list of values
    // Similar to a 2D array
    // quotedListPerLine[0] = List<string> containing { "125", "1.FC Nurnberg - TSV 1860 Munich", ... }
    // quotedListPerLine[1] = List<string> containing { "126","FC Ingolstadt 04 - TuS Koblenz", ... }
    r = new Regex("\"([^\"]+)\"", RegexOptions.IgnoreCase | RegexOptions.Compiled);
    foreach (string line in lineList)
    {
        List<string> quotedList = new List<string>();
        for (Match m = r.Match(line); m.Success; m = m.NextMatch())
        {
            quotedList.Add(m.Groups[1].Value);
        }
        quotedListPerLine.Add(quotedList);
    }

    return quotedListPerLine;
}

Calling code for your convenience:

List<List<string>> quotedListLines = MyRegEx.GetMatchesArrayPerLine(a);
foreach (List<string> line in quotedListLines)
{
    Console.WriteLine("----LINE---");
    foreach (string quotedText in line)
        Console.WriteLine(quotedText);
}

Rashmi Pandit 2009-05-22 10:32:51

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C# and Regex: How to extract strings between quotation marks

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