php Random Number Generator with rand Function

To generate a random number using php, the simplest way is to use the php rand() function:

echo rand(); // Output: 1123 
echo rand(0,10); // Output: 3

Random number generation with php is easy to do. All we need is the php rand() method.

The php rand() method generates random integers. There are two ways you can call rand() to generate a random integer.

First, if you want to generate a random integer between 0 and 2147483647 (this is platform dependent though), you can call rand() without passing the min and max parameters:

echo rand(); // Output: 4178 

If you want to generate a random number in a range of numbers using php, you can call rand() and pass the minimum and maximum of your range:

echo rand(10,20); // Output: 16 

You can also use the mt_rand() function which uses the Mersenne Twister algorithm to generate random numbers.

echo mt_rand(); // Output: 84761 

Generating Random Numbers in a Range in php

Generating random integers in a range of numbers using php is very easy. We can use the rand() or mt_rand() and pass the two numbers of our range to the function.

If we want to generate an integer between 0 and 100, we can do so with the following php code:

echo rand(0,100); // Output: 34 

Generating Random Floats in a Range with php

The rand() and mt_rand() functions only generate integers, so if we want to generate random float numbers in php, we need to create a function.

To generate a random float in php, we can use the function below:

function randomFloat($min = 0, $max = 1) {
    return $min + mt_rand()  * ($max - $min) / mt_getrandmax();
}

Let’s generate a few random floats in the range 20 to 30 – the following php code will do this for us:

function randomFloat($min = 0, $max = 1) {
    return $min + rand()  * ($max - $min) / getrandmax();
}

echo randomFloat(20,30); // Output: 28.981979893978
echo randomFloat(20,30); // Output: 20.341044915999
echo randomFloat(20,30); // Output: 21.3420155185

Using php to Generate Random Numbers in a Loop

Being able to generate one random number is great, but what if we want to generate many random numbers? We can generate multiple random numbers with php by using the rand() function and putting it in a loop.

Let’s generate 10 random numbers between 0 and 1 and stick them in an array.

function randomFloat($min = 0, $max = 1) {
    return $min + rand()  * ($max - $min) / getrandmax();
}

$random_array = array();

for ($x = 0; $x < 10; $x++) {
  array_push($random_array,randomFloat());
}

print_r($random_array);

// Output:
Array
(
    [0] => 0.39922291990333
    [1] => 0.71742709154143
    [2] => 0.97393983089083
    [3] => 0.046793667621349
    [4] => 0.076585880050708
    [5] => 0.59696800382667
    [6] => 0.66097702209883
    [7] => 0.77552434372507
    [8] => 0.54100747711072
    [9] => 0.12491378706177
)

Hopefully this article has been useful for you to understand how to generate a random number in a range of numbers using php.