Useful CSV parsing code

CSV.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CSV
{
    static bool EvenQuotes(string entry)
    {
        bool even = true;
        foreach (char letter in entry)
        {
            if (letter == '"')
            {
                even = !even;
            }
        }

        return even;
    }

    static string TrimQuotes(string entry)
    {
        // trim any whitespace
        entry = entry.Trim();

        // if begins with a quote
        if (entry.Length > 0 && entry[0] == '"')
        {
            // and ends with a quote
            if (entry[entry.Length - 1] == '"')
            {
                // remove trailing quotes
                entry = entry.Substring(1, entry.Length - 2);

                // quoted quotes
                if (entry.Contains("\"\""))
                {
                    // de-double the quotes
                    entry = entry.Replace("\"\"", "\"");
                }
            }
            else
            {
                // quote mismatch
                Debug.LogWarningFormat("Quote mismatch in entry '{0}'", entry);
            }
        }

        return entry;
    }

    static string ReplaceLineBreaks(string entry)
    {
        if (entry.Contains("\\n"))
        {
            // escape line breaks
            entry = entry.Replace("\\n", "\n");
        }

        return entry;
    }

    public static List<string> SplitCSVLine(string line)
    {
        string[] commaSeparated = line.Split(new char [] { ',' });
        List<string> entries = new List<string>();
        string entry = string.Empty;
        foreach (string segment in commaSeparated)
        {
            entry += segment;
            if (EvenQuotes(entry))
            {
                entries.Add(ReplaceLineBreaks(TrimQuotes(entry)));
                entry = string.Empty;
            }
            else
            {
                // re-add the trimmed comma
                entry += ",";
            }
        }

        if (entry != string.Empty)
        {
            Debug.LogWarningFormat("Found trailing text '{0}' while parsing CSV", entry);
        }

        return entries;
    }

    static string QuoteOutput(string entry)
    {
        // replace single quotes with double quotes
        entry = entry.Replace("\"", "\"\"");
        // de-escape line breaks
        entry = entry.Replace("\n", "\\n");

        if (entry.Contains(","))
        {
            // quote the entry
            entry = string.Format("\"{0}\"", entry);
        }

        return entry;
    }

    public static string MakeCSVLine(string[] entries)
    {
        string line = string.Empty;
        bool first = true;

        foreach (string entry in entries)
        {
            if (!first)
            {
                line += ",";
            }
            line += QuoteOutput(entry);
            first = false;
        }

        return line;
    }
}

I wasted hours looking for a simple CSV read and write. In the end I wrote some code to handle the cases I needed to worry about:

• quoted fields
• commas inside quoted fields
• newlines in fields (encoded as \n)

To turn an array of string into a CSV line call MakeCSVLine. To turn a CSV line into an array of strings call SplitCSVLine.