Select Random Datas From File

Question

Hello,

I'm learning C# and now I need to build a home project(just to learn how to use file I/O and random). I have a file(names.txt) like this:

Nathan
John
Max
Someone

But how I can access this file(already know) and select a random name, print it and delete this name from the file? Thanks.

Answer 1

Do you definitely need to delete the name from the file? Or can you just delete it from a list in memory?

Anyway, I would separate out the tasks this way:

• Load the text from the file e.g. with File.ReadAllLines
• Convert to a List<string> which will let you remove an element
• Create a new instance of System.Random
• Pick a random element using Random.Next()
• Fetch (and remove) the name from the list
• Print the name
• Write the file back with File.WriteAllLines

Now that you know the steps involved, have a go at each of them - and if you get stuck, ask for more details about a specific problem.

Answer 2

Try this :

using System;
using System.Diagnostics;
using System.IO;
using System.Linq;

namespace Tests.Console
{
    class Program
    {
        static void Main(string[] args)
        {
            string fileName = "c:\\toto.txt";
            var content = File.ReadAllLines(fileName).ToList();
            var selected = content[new Random().Next(0, content.Count)];

            Debug.Write(selected);

            content.Remove(selected);
            File.WriteAllLines(fileName, content.ToArray());
        }
    }
}