SelectMany

In this chapter you will learn:

How to use SelectMany operator
Select by both index and value

Get to know SelectMany operator

SelectMany concatenates subsequences into a single flat output sequence.

using System;//j  a v  a2 s  .c  om
using System.Collections;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
        string[] fullNames = { "A B", "C D E", "F G" };

        IEnumerable<string> query = fullNames.SelectMany(name => name.Split());

        foreach(String s in query){
           Console.WriteLine(s);
        }
    }
}

The output:

The following code selects char arrays from string array for each string value.

using System;//from   ja v  a 2  s. c o m
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"Ad", "Art", "Buch", "Bush", "Car", "land"};

        IEnumerable<char> chars = presidents.SelectMany(p => p.ToArray());

        foreach (char ch in chars)
            Console.WriteLine(ch);

    }
}

Select by both index and value

using System;//from  j a  va  2s.  c o  m
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"A", "Art", "Buch", "Bush", "Carter", "land"};

        IEnumerable<char> chars = presidents
         .SelectMany((p, i) => i < 5 ? p.ToArray() : new char[] { });

        foreach (char ch in chars)
            Console.WriteLine(ch);
    }
}

Next chapter...

What you will learn in the next chapter: