Random seed

In this post, I have listed several methods to generate a random number. However, sometimes you can see people using a random seed to generate one.

Why need a seed to create a random number?

Quick answer: if you want to have control of the random sequence or let other people generate the same sequence of random numbers, take a seed.

We should know that a random number generated by the computer is based on some algorithm written by programmers. It means that it is not 100% random like the random process that you find in nature. In other words, we call it pseudo-random.

The random generator is somehow complicated, but for demo purposes, I assume that:

   

So if you select the same seed, then you can have the same sequence.

seed in Python.

import random
random.seed(10)
print([random.randint(0, 9) for _ in range(5)])

if you run the code, you will always have the same sequence as mine:

[5, 4, 5, 2, 8]

seed in C#

using System;
public class Program
{
	public static void Main()
	{
		Console.WriteLine("Hello World");
		Random rdm = new Random(4);//seed = 4
		for(int i = 0; i < 5; i++){
			Console.Write(rdm.Next(9)+ " ");
		}
	}
}

And similarly, we have the same sequence :

7 8 5 3 0