Generating a random numbers and letters

Question

Can I ask for a certain code on how to generate a random letters and numbers in one word. I know there\'s a PHP function rand(), but I don\'t know if it\'s also applicable w

Answer 1

// A string with random letters and numbers. A-Z, a-z, 0-9


// A function in PHP is a block of code that can be used elsewhere in code.
// This function is called rand_string and will generate a random sequence of characters in one string.
// A default value of 16 characters is set, so that if no integer is supplied it will use the value of 16.
function rand_string($length = 16) {

    // A string is something that holds alphanumeric characters and other symbols. 
    // This string is an empty one, or at least that's how it starts.
    $string = '';

    // This is known as a for/next loop, it's will run a section of code for a set number of times.
    // A counter $i is incremented on each pass. In this case until it has operated $length number of times.
    for ($i = 0; $i < $length; $i++) {

        // This variable ($die) is assigned a random number - which is obtained via the PHP function mt_rand.
        //Consult the PHP docs for more information.
        $die = mt_rand(1, 3);

        // This switch statement picks a case that is true and runs the accompanying code as defined in each case.
        switch ($die) {

            // This case will be activated if the variable $die has the value of 1. And case 2 if it has the value of 2 and so on.
            case 1:
                // Here and subsequently a random value between 48 and 57 is assigned to the $rnd variable.
                $rnd = mt_rand(48, 57);
                break;

            case 2:
                $rnd = mt_rand(65, 90);
                break;

            case 3:
                $rnd = mt_rand(97, 122);
                break;
        }

        // This is another variable $string which is assigned the ASCII character that is represented by the $rnd variable.
        // ASCII characters are codes that computers use to represent characters and symbols.
        // The chr function is a special PHP function that returns the character represented by the ASCII code.
        // In this case the value of $rnd.
        $string .= chr($rnd);
    }

    // Here we reach the final result. The value of $string is returned to source of the function call.
    return $string;
}

// Segments of the function, loops and switches are enclosed between curly brackets {}. This limits the scope of the processing contained within.

// Usage of this function to obtain a 10 character random string.
// echo is a function that prints the result to the browser/screen.
$mystring = rand_string(10);
echo $mystring;