Delimit a string by character unless within quotation marks C#

Question

I need to demilitarise text by a single character, a comma. But I want to only use that comma as a delimiter if it is not encapsulated by quotation marks.

An example:

Method,value1,value2

Would contain three values: Method, value1 and value2

But:

Method,"value1,value2"

Would contain two values: Method and "value1,value2"

I'm not really sure how to go about this as when splitting a string I would use:

String.Split(',');

But that would demilitarise based on ALL commas. Is this possible without getting overly complicated and having to manually check every character of the string.

Thanks in advance

Use an available csv parser like [`VisualBasic.FileIO.TextFieldParser`](https://msdn.microsoft.com/en-us/library/microsoft.visualbasic.fileio.textfieldparser(v=vs.110).aspx) or [this](http://www.codeproject.com/Articles/9258/A-Fast-CSV-Reader) or [this](http://www.filehelpers.com/). — Tim Schmelter, Jun 29 '15 at 14:58
[Potential dupe](http://stackoverflow.com/questions/4829779/splitting-a-csv-and-excluding-commas-within-elements), but highest upvoted/accepted answer is a link only answer... (to one of the articles @Tim just edited in :)) — James Thorpe, Jun 29 '15 at 15:00
For completion.. would you mind giving an example of usage for the TextFieldParser for my situation? So I can accept as answer. Thanks for quick responses :) — Zephni, Jun 29 '15 at 15:03
possible duplicate of [Read csv file c# with comma separator](http://stackoverflow.com/questions/29678507/read-csv-file-c-sharp-with-comma-separator) — David Arno, Jun 29 '15 at 15:04
possible duplicate of [Parse comma seperated string with a complication in C#](http://stackoverflow.com/questions/30078054/parse-comma-seperated-string-with-a-complication-in-c-sharp) - *The complication is quotes* — Alex K., Jun 29 '15 at 15:04
you can skip character. create method that replace char ',' inside '"' with something else (ex: `\u9999`) then split and finally replace skipped char with ',' — M.kazem Akhgary, Jun 29 '15 at 15:09

Tim Schmelter · Accepted Answer · 2015-06-29T15:17:42.343

2

Copied from my comment: Use an available csv parser like VisualBasic.FileIO.TextFieldParser or this or this.

As requested, here is an example for the TextFieldParser:

var allLineFields = new List<string[]>();
string sampleText = "Method,\"value1,value2\"";
var reader = new System.IO.StringReader(sampleText);
using (var parser = new Microsoft.VisualBasic.FileIO.TextFieldParser(reader))
{
    parser.Delimiters = new string[] { "," };
    parser.HasFieldsEnclosedInQuotes = true; // <--- !!!
    string[] fields;
    while ((fields = parser.ReadFields()) != null)
    {
        allLineFields.Add(fields);
    }
}

This list now contains a single string[] with two strings. I have used a StringReader because this sample uses a string, if the source is a file use a StreamReader(f.e. via File.OpenText).

edited Jun 29 '15 at 15:17

answered Jun 29 '15 at 15:14

Tim Schmelter

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Don't suppose you have any insights into why a useful class like this is buried in the VisualBasic namespace? – James Thorpe Jun 29 '15 at 15:17
@JamesThorpe: you are asking the wrong person. That can only be answered by someone who belonged to the VB.NET/C# compiler team. I guess that such utility classes were important for VB.NET but not for the C# guys. However, since it belongs to the .NET framework you can use it also with C# by adding the reference to the Microsoft.VisualBasic.dll. – Tim Schmelter Jun 29 '15 at 15:19
Yeah fair enough - always just seems odd when I see things like this in there and not "part of" the wider framework. I can understand things to bring forward VB6 style functions etc, but not stuff like this. Anyway... offtopic for here. – James Thorpe Jun 29 '15 at 15:22
Thank you very much, this does exactly the job I was looking for and easy to put in it's own method. :) I also wondered why it is only available in the VisualBasic namespace – Zephni Jun 29 '15 at 15:25

score 1 · Answer 2 · answered Jun 29 '15 at 15:25

You can try Regex.Split() to split the data up using the pattern

",|(\"[^\"]*\")"

This will split by commas and by characters within quotes.

Code Sample:

using System;
using System.Linq;
using System.Text.RegularExpressions;

public class Program
{
    public static void Main()
    {
        string data = "Method,\"value1,value2\",Method2";
        string[] pieces = Regex.Split(data, ",|(\"[^\"]*\")").Where(exp => !String.IsNullOrEmpty(exp)).ToArray();

        foreach (string piece in pieces)
        {
            Console.WriteLine(piece);
        }
    }
}

Results:

Method
"value1,value2"
Method2

Demo

Delimit a string by character unless within quotation marks C#

2 Answers2