Selecting alternate items of an array C#

Question

I have an array statsname as

apple
X
banana
Y
Kiwi
z

I need to put apple,banana and Kiwi in an array Fruits and X,Y and Z in an array calle

Answer 1

using only Arrays:

 var array = new string[] { "apple", "X", "banana", "Y", "Kiwi", "z" };
 var fruit = new string[array.Length];
 var alphabet = new string[array.Length];
 for(var i = 0,j = 0; i < array.Length / 2; i++, j += 2)
 {
     fruit[i] = array[j];               
     alphabet[i] = array[j + 1];
 }

Answer 2

Stolen from How to get Alternate elements using Enumerable in C#

var fruits = myArray.Where((t, i) => i % 2 == 0).ToArray();
var alphabets = myArray.Where((t, i) => i % 2 == 1).ToArray();

Answer 3

You could make an iterator which just skips every other element. The idea is to have a "view" of a collection, special enumerable which will return only some of the elements:

  static IEnumerable<T> everyOther<T>( IEnumerable<T> collection )
  {
    using( var e = collection.GetEnumerator() ) {
      while( e.MoveNext() ) {
        yield return e.Current;
        e.MoveNext(); //skip one
      }
    }
  }

You can use System.Linq.Skip to skip the first element.

string[] words = "apple X banana Y Kiwi z".Split();

var fruits = everyOther( words );
var alphabets = everyOther( words.Skip(1) );

Just use them as a new collection or call .ToArray() or .ToList() on them:

foreach( string f in fruits )
  Console.WriteLine( f );

string[] anArray = fruits.ToArray();  //using System.Linq

Now you have what you need.

Iterators are methods which yield return, see Iterators (C# Programming Guide). This is very strong feature of the language. You can:

• skip elements
• decorate elements
• change ordering
• concatenate sequences (see System.Linq.Concat)
• ...

Answer 4

string[] rawarray = new string [] {"Apple","X" .....};
string[] Fruites = new string[rawarray.Length/2+1];
string[] Alphabets = new string[rawarray.Length/2];

For(int i=0; i<rawarray.Length;i++)
{
   if(i%2==0)
   {
     Fruits[i/2]=rawarray[i]; 
   }
   else
   {
     Alphabets[i/2]=rawarray[i]; 
   }   
}

Answer 5

Single LINQ:

List<string> list = new List<string>() { "apple", "X", "banana", "Y", "Kiwi", "z" };
var result = list.Select((l, i) => new { l, i })
                 .GroupBy(p => p.i % 2)
                 .Select(x => x.Select(v => v.l).ToList())
                 .ToList();

Then you have a list of lists:

Answer 6

Use the IEnumerable<T>.Where overload which supplies the index.

var fruits = statsname.Where((s, i) => i % 2 == 0).ToArray();
var alphabets = statsname.Where((s, i) => i % 2 != 0).ToArray();