Generating a random numbers and letters - php

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 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!

Answer 1

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

Answer 2

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.

Answer 3

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");

Answer 4

Use uniqid
$desired_length = 10; //or whatever length you want
$unique = uniqid();
$your_random_word = substr($unique, 0, $desired_length);

Answer 5

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;
}

Answer 6

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)];
}

Answer 7

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;

Answer 8

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

Answer 9

echo bin2hex(openssl_random_pseudo_bytes(12));

Answer 10

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

Answer 11

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/

Answer 12

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();

Answer 13

// 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;

Answer 14

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.