String[] arr = new[] { "1", "123" };            IEnumerable
     
       arrSelectIndex = arr.Select
      
       ((s, i) => Convert.ToInt32(s) + i);            foreach (int i in arrSelectIndex)            {                Console.WriteLine(i);            }            IEnumerable
       
         arrSelect = arr.Select
        
         (s => Convert.ToInt32(s)).ToList();            foreach (var s in arrSelect)            {                Console.WriteLine(s);            }