Question

I need to write a function which will randomize some words of my string. For example:

[Hello|Hi] guys. This is my [code|string]

The function should return:

Hello guys. This is my code

or

Hi guys. This is my string

Answer 1

You can get a random number generator like this:

var rand = new Random();

As for parsing your string and getting all of the options, I suggest you look into System.Text.RegularExpressions

The other answers so far have just shown how you can get a random string if you already have one or two options for the different placeholders. Those are fine, but pretty boring and tedious to write out. It’s much better to write a parser that can take a random string “template” like the OP gave, and use that to generate the random strings.

Here is a quick one I put together:

using System;
using System.Text.RegularExpressions;

namespace StackOverLoadTest {
static class Program {
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main() {
        var s = new RandomString("[Hey|Hi] guys. [I|You|We|He|She] should [walk] to the [park|field|farm] sometime [today|tomorrow|next week].");
        for (int i = 0; i < 10; i++)
            Console.WriteLine(s);
    }
}

public class RandomString {
    private Random _rnd = new Random();
    private static Regex _rex = new Regex(@"\[ ( \|?  (?<option>[^]|]+) )+ \]", System.Text.RegularExpressions.RegexOptions.IgnorePatternWhitespace | System.Text.RegularExpressions.RegexOptions.ExplicitCapture);
    string _template;
    public RandomString(string template) {
        _template = template;
    }
    public override string ToString() {
        return _rex.Replace(_template, GetRandomOption);
    }
    public string GetRandomOption(Match m) {
        var options = m.Groups["option"].Captures;
        int choice = _rnd.Next(0, options.Count);
        return options[choice].Value;
    }
}
}

As you can see, you use create a new RandomString object with the template. Then simply call the ToString() function as many time as you want, and each time you get a new random permutation of the options.

You can use any number of placeholders with any number of options (except 0).
The string template I used in this example was:


"[Hey|Hi] guys. [I|You|We|He|She] should [walk] to the [park|field|farm] sometime [today|tomorrow|next week]."


Running the code above, I got the following results:



Hey guys. I should walk to the park sometime today.
Hi guys. We should walk to the farm sometime today.
Hi guys. He should walk to the field sometime next week.
Hey guys. You should walk to the park sometime next week.
Hi guys. She should walk to the farm sometime next week.
Hey guys. We should walk to the field sometime tomorrow.
Hi guys. I should walk to the farm sometime today.
Hey guys. He should walk to the field sometime tomorrow.
Hi guys. You should walk to the park sometime next week.
Hi guys. I should walk to the farm sometime today.