Converting a List<int> to a comma separated string

Is there a way to take a List and convert it into a comma separated string?

I know I can just loop and build it, but somehow I think some of you guys a more cool way of doing it?

I really want to learn these types of 'tricks', so please explain or link to the docs on the method you use.

Solution 1:

List<int> list = ...;
string.Join(",", list.Select(n => n.ToString()).ToArray())

Solution 2:

Simple solution is

List<int> list = new List<int>() {1,2,3};
string.Join<int>(",", list)

I used it just now in my code, working funtastic.

Solution 3:

List<int> list = new List<int> { 1, 2, 3 };
Console.WriteLine(String.Join(",", list.Select(i => i.ToString()).ToArray()));

Solution 4:

For approximately one gazillion solutions to a slightly more complicated version of this problem -- many of which are slow, buggy, or don't even compile -- see the comments to my article on this subject:

https://docs.microsoft.com/en-us/archive/blogs/ericlippert/comma-quibbling

and the StackOverflow commentary:

Eric Lippert's challenge "comma-quibbling", best answer?

Solution 5:

For extra coolness I would make this an extension method on IEnumerable<T> so that it works on any IEnumerable:

public static class IEnumerableExtensions {
  public static string BuildString<T>(this IEnumerable<T> self, string delim = ",") {
    return string.Join(delim, self)        
  }
}

Use it as follows:

List<int> list = new List<int> { 1, 2, 3 };
Console.WriteLine(list.BuildString(", "));