C# Enumerable Select(IEnumerable, Func)

Description

Projects each element of a sequence into a new form by incorporating the element's index.

Syntax

public static IEnumerable<TResult> Select<TSource, TResult>(
  this IEnumerable<TSource> source,
  Func<TSource, int, TResult> selector
)

Parameters

• TSource - The type of the elements of source.
• TResult - The type of the value returned by selector.
• source - A sequence of values to invoke a transform function on.
• selector - A transform function to apply to each source element; the second parameter of the function represents the index of the source element.

Example

The following code example demonstrates how to use Select to project over a sequence of values and use the index of each element.

/*  w  ww.  ja  v  a 2 s  .  c  om*/
using System;
using System.Linq;
using System.Collections.Generic;
public class MainClass{
  public static void Main(String[] argv){  
     string[] myData = { "Java", "Java XML", };

     var query = myData.Select((fruit, index) =>
                           new { index, str = fruit.Substring(0, index) });

     foreach (var obj in query)
     {
         Console.WriteLine("{0}", obj);
     }

  }
}
    

The code above generates the following result.