fun with random number

October 19, 2023

introduction

A random number is a number generated using a large set of numbers and a mathematical algorithm which gives equal probability to all numbers occurring in the specified distribution, which are most commonly produced with the help of a random number generator ( Rouse, 2016 ).
It is a number which is generated for, or part of, a set exhibiting statistical randomness, where the statistical randomness is a characteristic where a numeric sequence is said to be statistically random when it contains no recognisable patterns or regularities ( WHS, 2021 ).
A random number is a number chosen as if by chance from some specified distribution such that selection of a large set of these numbers reproduces the underlying distribution and almost always, such numbers are also required to be independent, so that there are no correlations between successive numbers ( Weisstein, 2023 ).

random function

There is a function to generate random float number ( MND, 2023 )

The Math.random() static method returns a floating-point, pseudo-random number that’s greater than or equal to 0 and less than 1, with approximately uniform distribution over that range — which you can then scale to your desired range. The implementation selects the initial seed to the random number generation algorithm; it cannot be chosen or reset by the user.

random number $\in [0, 1)$

Result
```
0.7322
0.7564
0.5447
0.5297
0.0453
0.2310
0.4751
0.9178
0.1715
0.5252
```

Code https://onecompiler.com/javascript/3zqvkr9k2

// set repetition
N = 10;

// set digit
M = 4

// generate random number
for(var i = 0; i < N; i++) {
  x = Math.random();
  xs = x.toFixed(M)
  console.log(xs);
}

integer random number

Result
```
[
  7, 4, 2, 5, 5, 4, 4, 5, 4, 4,
  2, 9, 7, 5, 4, 2, 6, 3, 4, 2,
  7, 6, 5, 5, 8, 7, 9, 3, 8, 8,
  3, 8, 6, 8, 9, 3, 2, 2, 3, 2
]
```
Code https://onecompiler.com/javascript/3zqvnpgc7

// set repetition
N = 40;

// set range of integer
imin = 2;
imax = 9;


// create empty array
a = [];

// generate random number
for(var i = 0; i < N; i++) {
  x = Math.random();
  y = x * (imax - imin + 1) + imin;
  z = Math.floor(y);
  a.push(z);
}

console.log(a);

randint in-house function

Result

[
  11, 11, 11, 11, 12, 12, 13, 13, 13, 13, 14, 14,
  15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16,
  16, 16, 17, 17, 17, 18, 18, 18, 19, 20, 20, 21,
  21, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23,
  24, 24, 24, 24, 25, 25, 25, 25, 26, 26, 26, 26,
  27, 27, 28, 28, 28, 28, 28, 28, 29, 29, 29, 30,
  30, 30, 31, 31, 31, 31, 31, 32, 32, 33, 33, 33,
  35, 35, 35, 36, 36, 36, 37, 37, 37, 37, 37, 39,
  39, 40, 40, 40
]
[
  25, 26, 12, 22, 25, 33, 21, 28, 16, 40, 13, 16,
  13, 31, 24, 18, 24, 28, 25, 23, 35, 22, 22, 37,
  37, 16, 22, 32, 31, 28, 33, 20, 15, 31, 36, 31,
  29, 26, 30, 37, 29, 31, 37, 15, 15, 23, 13, 15,
  39, 36, 22, 21, 27, 37, 30, 11, 18, 16, 17, 14,
  20, 13, 17, 32, 35, 25, 19, 28, 23, 11, 40, 33,
  24, 15, 17, 26, 16, 15, 29, 26, 28, 16, 24, 16,
  35, 11, 23, 16, 18, 27, 14, 36, 28, 22, 11, 30,
  12, 40, 39, 23
]

Code https://onecompiler.com/javascript/3zqvpgq53

// create randint function
function randint(imin, imax) {
  x = Math.random();
  y = x * (imax - imin + 1) + imin;
  z = Math.floor(y);
  return z;
}

// create randintn
function randintn(imin, imax, N) {
  a = [];
  for(var i = 0; i < N; i++) {
    a.push(randint(imin, imax))
  }
  return a;
}

// create array of integer random numbers
x = randintn(11, 40, 100)
y = [...x];
console.log(y.sort());
console.log(x);

application(s)

Random HTTP headers User-Agent: One way to reduce being blocked while web scraping .