C# Regex Split - commas outside quotes

Question

Hey,

I got quite a lot of strings (segments of SQL code, actually) with the following format:

('ABCDEFG', 123542, 'XYZ 99,9')

and i need to split this string, using C#, in order to get:

• 'ABCDEFG'
• 123542
• 'XYZ 99,9'

I was originally using a simple Split(','), but since that comma inside the last parameter is causing havoc in the output i need to use Regex to get it. The problem is that i'm still quite noobish in regular expressions and i can't seem to crack the pattern mainly because inside that string both numerical and alpha-numerical parameters may exist at any time...

What could i use to split that string according to every comma outside the quotes? Cheers

Answer 1

You could split on all commas, that do have an even number of quotes following them , using the following Regex to find them:

",(?=(?:[^']*'[^']*')*[^']*$)"

You'd use it like

var result = Regex.Split(samplestring, ",(?=(?:[^']*'[^']*')*[^']*$)");

Answer 2

Try (hacked from Jens') in the split method:

",(?:.*?'[^']*?')"

or just add question marks after Jens' *'s, that makes it lazy rather than greedy.

Answer 3

hi guys!

although I too like a challenge some of the time, but this actually isn't one. please read this article http://secretgeek.net/csv_trouble.asp and then go on and use http://www.filehelpers.com/

[Edit1, 3]: or maybe this article can help too (the link only shows some VB.Net sample code but still, you can use it with C# too!): http://msdn.microsoft.com/en-us/library/cakac7e6.aspx

I've tried to do the sample for C# (add reference to Microsoft.VisualBasic to your project)

using System;
using System.IO;
using Microsoft.VisualBasic.FileIO;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            TextReader reader = new StringReader("('ABCDEFG', 123542, 'XYZ 99,9')");
            TextFieldParser fieldParser = new TextFieldParser(reader);

            fieldParser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited;
            fieldParser.SetDelimiters(",");

            String[] currentRow; 

            while (!fieldParser.EndOfData)
            {
                try
                {
                     currentRow = fieldParser.ReadFields();

                     foreach(String currentField in currentRow)
                     {
                        Console.WriteLine(currentField);                        
                     }
                }
                catch (MalformedLineException e)
                {
                    Console.WriteLine("Line {0} is not valid and will be skipped.", e);
               }

            } 

        }
    }
}

[Edit2]: found another one which could be of help here: http://www.codeproject.com/KB/database/CsvReader.aspx

-- reinhard