Most efficent way of joining strings

Question

I need to concatenate a lot of strings alltogether and put a comma between any of them. I have a list of strings

\"123123123213\"
\"1232113213213\"
\"1232131         


        

Answer 1

As @Ekkehard said, use the string.Join.

However, you do not need the ToArray() because string.Join has an overload for IEnumerable.

List stringList = new List 
    { "1234567890", "34343434", "4343434" }; 

string outcome = string.Join(",", stringList);

EDIT

As @Kobi said, this will work only C# 4.0. In 3.5 I would do.

var s = new StringBuilder(stringList.Count * 8);
foreach (var item in stringList)
{
   s.Append(item);
   s.Append(',');
}
s.Length -= 1;
string outcome = stringList.ToList();