In C#: Add Quotes around string in a comma delimited list of strings

Question

This probably has a simple answer, but I must not have had enough coffee to figure it out on my own:

If I had a comma delimited string such as:

string li         


        

Answer 1

string list = "Fred,Sam,Mike,Sarah";

string[] splitList = list.Split(',');

for (int i = 0; i < splitList.Length; i++)
    splitList[i] = String.Format("'{0}'", splitList[i]);

string newList = String.Join(",", splitList);

Answer 2

The C# implementation of @PhiLho's JavaScript regular expression solution looks something like the following:

Regex regex = new Regex(
    @"\b",
    RegexOptions.ECMAScript
    | RegexOptions.Compiled
    );

string list = "Fred,Sam,Mike,Sarah";
string newList = regex.Replace(list,"'");

Answer 3

string s = "A,B,C";
string replaced = "'"+s.Replace(",", "','")+"'";

Thanks for the comments, I had missed the external quotes.

Of course.. if the source was an empty string, would you want the extra quotes around it or not ? And what if the input was a bunch of whitespaces... ? I mean, to give a 100% complete solution I'd probably ask for a list of unit tests but I hope my gut instinct answered your core question.

Update: A LINQ-based alternative has also been suggested (with the added benefit of using String.Format and therefore not having to worry about leading/trailing quotes):

string list = "Fred,Sam,Mike,Sarah";
string newList = string.Join(",", list.Split(',').Select(x => string.Format("'{0}'", x)).ToList());

Answer 4

string[] bits = list.Split(','); // Param arrays are your friend
for (int i=0; i < bits.Length; i++)
{
    bits[i] = "'" + bits[i] + "'";
}
return string.Join(",", bits);

Or you could use LINQ, particularly with a version of String.Join which supports IEnumerable<string>...

return list.Split(',').Select(x => "'" + x + "'").JoinStrings(",");

There's an implementation of JoinStrings elsewhere on SO... I'll have a look for it.

EDIT: Well, there isn't quite the JoinStrings I was thinking of, so here it is:

public static string JoinStrings<T>(this IEnumerable<T> source, 
                                    string separator)
{
    StringBuilder builder = new StringBuilder();
    bool first = true;
    foreach (T element in source)
    {
        if (first)
        {
            first = false;
        }
        else
        {
            builder.Append(separator);
        }
        builder.Append(element);
    }
    return builder.ToString();
}

These days string.Join has a generic overload instead though, so you could just use:

return string.Join(",", list.Split(',').Select(x => $"'{x}'"));