C#, Regular Expressions:How to Parse Comma-Separated Values, Where Some Values Might Be Quoted Strings Themselves Containing Commas

C#, regular expressions : how to parse comma-separated values, where some values might be quoted strings themselves containing commas

Try with this Regex:

"[^"\r\n]*"|'[^'\r\n]*'|[^,\r\n]*

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    Regex regexObj = new Regex(@"""[^""\r\n]*""|'[^'\r\n]*'|[^,\r\n]*");
    Match matchResults = regexObj.Match(input);
    while (matchResults.Success) 
    {
        Console.WriteLine(matchResults.Value);
        matchResults = matchResults.NextMatch();
    }

Ouputs:

• cat
• dog
• "0 = OFF, 1 = ON"
• lion
• tiger
• 'R = red, G = green, B = blue'
• bear

Note: This regex solution will work for your case, however I recommend you to use a specialized library like FileHelpers.

C# Regex Split - commas outside quotes

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

C# split comma separated values

It's because of the capture group. Just turn it into a non-capture group:

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

The capture group is including the captured part in your results.

ideone demo

var regexObj = new Regex(@",(?=(?:[^""]*""[^""]*"")*[^""]*$)");
regexObj.Split(input).Select(s => s.Trim('\"', ' ')).ForEach(Console.WriteLine);

And just trim the results.

C# text split logic comma separator and string identifier

This is the situation where TextFieldParser in the Microsoft.VisualBasic.FileIO library is best fit.

using Microsoft.VisualBasic.FileIO; //add this

static void Main(string[] args)
{
    string text = System.IO.File.ReadAllText(@"D://dtl.txt"); //note this

    List<string[]> param = new List<string[]>();
    string[] words; //add intermediary reference

    using (TextFieldParser parser = new TextFieldParser(new StringReader(text))) {
        parser.Delimiters = new string[] { "," }; //the parameter must be comma
        parser.HasFieldsEnclosedInQuotes = true;
        while ((words = parser.ReadFields()) != null)
            param.Add(words);
    }

    var x = param; // for debug
}

And you shall get what you need. Read this.

Output:

array : 
[0] : "AWD_CODE","AWD_NAME","AWD_TYPE","ADF_REF","FLG_SUM","FLG"
[1] : "DMM","PETCH","01","REF 2/2015","",""
[2] : "TRR","TUCTH","01","REF 2/2015","WD_TRK","F"
[3] : "TGC","DHYTH","02","REF 3/2015","WD_TRK,WD_TRI","F"

To use it, you need to include Microsoft.VisualBasic in your reference.

Using Regular Expressions for Pattern Finding with Replace

Personally, I'd avoid regexes here - assuming that there aren't nested quote marks, this is quite simple to write up as a for-loop, which I think will be more efficient:

var inQuotes = false;
var sb = new StringBuilder(someText.Length);

for (var i = 0; i < someText.Length; ++i)
{
    if (someText[i] == '"')
    {
        inQuotes = !inQuotes;
    }

    if (inQuotes && someText[i] == ',')
    {
        sb.Append('$');
    }
    else
    {
        sb.Append(someText[i]);
    }
}

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