How String Join in C# works??

Answer 1

The string.Join method combines many strings into one. It receives an array or IEnumerable type and a separator string. It places the separator string between every element of the collection in the returned string.

Example program:

using System;
using System.Text;

class Program
{
    static void Main()
    {
    string[] catSpecies = { "Aegean", "Birman", "Main Coon", "Nebulung" };
    Console.WriteLine(CombineA(catSpecies));
    Console.WriteLine(CombineB(catSpecies));
    }

    /// <summary>
    /// Combine strings with commas.
    /// </summary>
    static string CombineA(string[] arr)
    {
    return string.Join(",", arr);
    }

    /// <summary>
    /// Combine strings with commas.
    /// </summary>
    static string CombineB(string[] arr)
    {
    StringBuilder builder = new StringBuilder();
    foreach (string s in arr)
    {
        builder.Append(s).Append(",");
    }
    return builder.ToString().TrimEnd(new char[] { ',' });
    }
}

Output :
Aegean,Birman,Main Coon,Nebulung
Aegean,Birman,Main Coon,Nebulung