Generating a random numbers and letters

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开发者_如何学运维 applicable with letters. There's also a function called mt_rand() but I don't know how it works. I'm planning on generating a word like this one:

$randomcode = re784dfg7ert7;

Do you guys have any simple code on this one? Thanks in advance!

<?php
echo substr(sha1(mt_rand()),17,6); //To Generate Random Numbers with Letters.
?>

This is a more extensive method that I use constantly to generate random numbers, letters or mixed:

function assign_rand_value($num) {

    // accepts 1 - 36
    switch($num) {
        case "1"  : $rand_value = "a"; break;
        case "2"  : $rand_value = "b"; break;
        case "3"  : $rand_value = "c"; break;
        case "4"  : $rand_value = "d"; break;
        case "5"  : $rand_value = "e"; break;
        case "6"  : $rand_value = "f"; break;
        case "7"  : $rand_value = "g"; break;
        case "8"  : $rand_value = "h"; break;
        case "9"  : $rand_value = "i"; break;
        case "10" : $rand_value = "j"; break;
        case "11" : $rand_value = "k"; break;
        case "12" : $rand_value = "l"; break;
        case "13" : $rand_value = "m"; break;
        case "14" : $rand_value = "n"; break;
        case "15" : $rand_value = "o"; break;
        case "16" : $rand_value = "p"; break;
        case "17" : $rand_value = "q"; break;
        case "18" : $rand_value = "r"; break;
        case "19" : $rand_value = "s"; break;
        case "20" : $rand_value = "t"; break;
        case "21" : $rand_value = "u"; break;
        case "22" : $rand_value = "v"; break;
        case "23" : $rand_value = "w"; break;
        case "24" : $rand_value = "x"; break;
        case "25" : $rand_value = "y"; break;
        case "26" : $rand_value = "z"; break;
        case "27" : $rand_value = "0"; break;
        case "28" : $rand_value = "1"; break;
        case "29" : $rand_value = "2"; break;
        case "30" : $rand_value = "3"; break;
        case "31" : $rand_value = "4"; break;
        case "32" : $rand_value = "5"; break;
        case "33" : $rand_value = "6"; break;
        case "34" : $rand_value = "7"; break;
        case "35" : $rand_value = "8"; break;
        case "36" : $rand_value = "9"; break;
    }
    return $rand_value;
}

function get_rand_alphanumeric($length) {
    if ($length>0) {
        $rand_id="";
        for ($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(1,36);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}

function get_rand_numbers($length) {
    if ($length>0) {
        $rand_id="";
        for($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(27,36);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}

function get_rand_letters($length) {
    if ($length>0) {
        $rand_id="";
        for($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(1,26);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}

USAGE:

Basically I have a main function with the array, then I call secondary functions to build my string based on the length parameter:

Letters:

$str = get_rand_letters(8); // Only Letters

Numbers:

$str = get_rand_numbers(8); // Only Numbers

AlphaNumeric:

$str = get_rand_alphanumeric(8); // Numbers and Letters

This Question is answered by Kerrek SB, but this may help someone searching for a more extensive and flexible way.

Step 1: Create an alphabet, $alph = "0123456789abcde...";.

Step 2: Create a random number, $n = rand(0, ALPHSIZE-1);, or use mt_rand().

Step 3: Get the appropriate index in the alphabet: $alph[n];

Rinse and repeat steps 2 and 3 for as many times as you need characters.

If you want strong statistical properties (like uniformness), you should work a little harder with the random number, but this should get you started. (I think the statistical properties of that should be sufficient.)

OK, might as well spell it out:

$alph = "012...";
function make_random_string($N)
{
  $s = "";
  for ($i = 0; $i != $N; ++$i)
    s .= $alph[mt_rand(0, ALPHSIZE - 1)];
  return $s;
}

And here's the version that takes a custom alphabet:

function make_random_custom_string($N, $alphabet)
{
  $s = "";
  for ($i = 0; $i != $N; ++$i)
    s .= $alphabet[mt_rand(0, strlen($alphabet) - 1)];
  return $s;
}

Example: 10 random odd digits: make_random_custom_string(10, "13579");

Use uniqid

$desired_length = 10; //or whatever length you want
$unique = uniqid();

$your_random_word = substr($unique, 0, $desired_length);

It might be done this way:

function RandomCode($length = 10)
{
    $code = '';
    $total = 0;

    do
    {
        if (rand(0, 1) == 0)
        {
            $code.= chr(rand(97, 122)); // ASCII code from **a(97)** to **z(122)**
        }
        else
        {
            $code.= rand(0, 9); // Numbers!!
        }
        $total++;
    } while ($total < $length);

    return $code;
}

This was an easy way for me- this generates a 15 character string -

        $alph = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        $code='';

        for($i=0;$i<15;$i++){
           $code .= $alph[rand(0, 35)];
        }

Try this, it worked for me.

$numLenth = 35;

function make_seed_Token() {
  list($usec, $sec) = explode(' ', microtime());
  return (float) $sec + ((float) $usec * 100000);
}

srand(make_seed_Token());

$numSeed = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
$getNumber = "";
for($i = 0; $i < $numLenth; $i ++) {
 $getNumber .= $numSeed[rand(0, strlen($numSeed))];

}

echo $getNumber;

What about this simple code. This will generate 10 characters,you can limit characters by modifying the limits (0,10)

$str = substr(md5(time()), 0, 10);
echo $str; //7aca159655

echo bin2hex(openssl_random_pseudo_bytes(12));

function randText($len=4){
    $str = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    for($i=0;$i<$len;$i++){
        $txt.=substr($str, rand(0, strlen($str)), 1);   
    }
return $txt;
}

to use simply type:

$yourVar = randText(10);  // to get 10char long text

I put together a PHP class for generating random numbers and strings PHPRandomValue,

It uses "mcrypt_create_iv(4, MCRYPT_DEV_URANDOM)" to generate random numbers and values. I made it while working on a crypto project because I needed a safe random value generator and mt_rand() doesn't meet that requirement. Here's an example usage

$randomValue = new RandomValue;

$randomValue->randomNumber(): = -3880998

$randomValue->randomNumberBetween(1,10): = 2

$randomValue->randomTextString(): = CfCkKDHRgUULdGWcSqP4

$randomValue->randomTextString(10):  = LorPIxaeEY

$randomValue->randomKey(): = C7al8tX9.gqYLf2ImVt/!$NOY79T5sNCT/6Q.$!.6Gf/Q5zpa3

$randomValue->randomKey(10):  = RDV.dc6Ai/

This will create random alpha num string based on variable chars:

function createRandomCode() 
{     
    $chars = "abcdefghijkmnopqrstuvwxyz023456789";     
    srand((double) microtime() * 1000000);     

    $i = 0;     
    $pass = '';  

    while ($i <= 7) 
    {         
        $num = rand() % 33;         
        $tmp = substr($chars, $num, 1);         
        $pass = $pass . $tmp;         
        $i++;     
    }    

    return $pass; 
}

Use this function as $random = createRandomCode();

// 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;

Easiest way to do this with full control:

<?php
$str = 'QaR0SbT1UcV2WdX3YeZ4f5g6h7i8j9kAlBmCnDoEpFqGrHsItJuKvLwMxNyOzP';
// a-z 0-9 A-Z in above string

$shuffled = str_shuffle($str);

$shuffled = substr($shuffled,1,30);

echo $shuffled;
?>

Change $str according to your needs. I used small alphabets a to z, capital alphabets A to Z and numeric values 0 to 9.