How to create 6 digit OTP with 2 digits and 4 alphabets? - php

Question

I have a script which generates 6 character One Time Password (OTP).
Here is the code:-
$seed = str_split('ABCDEFGHIJKLMNOPQRSTUVWXYZ'.'0123456789'); // and any other characters
shuffle($seed); // probably optional since array_is randomized; this may be redundant
$rand = '';
foreach (array_rand($seed, 6) as $k)
$rand .= $seed[$k];
$feedID = $rand;
Now, due to shuffling procedure, currently all 6 can be digits, all 6 can be alphabets.
I want min and max 2 mandatory digits.
How can I do that?

Answer 1

Here's my take on it:
// Create a string of all alpha characters and randomly shuffle them
$alpha = str_shuffle('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
// Create a string of all numeric characters and randomly shuffle them
$numeric = str_shuffle('0123456789');
// Grab the 4 first alpha characters + the 2 first numeric characters
$code = substr($alpha, 0, 4) . substr($numeric, 0, 2);
// Shuffle the code to get the alpha and numeric in random positions
$code = str_shuffle($code);
If you want the possibility to have any character more than once, change the two first lines (quick and dirty):
// Let's repeat this string 4 times before shuffle, since we need 4 characters
$alpha = str_shuffle(str_repeat('ABCDEFGHIJKLMNOPQRSTUVWXYZ', 4));
// Let's repeat this string 2 times before shuffle, since we need 2 numeric characters
$numeric = str_shuffle(str_repeat('0123456789', 2));
Not saying that this is the best way of doing it, but it's simple, without loops and/or arrays. :)

Answer 2

One more option.
Not saying that this is the best way of doing it, but it's simple, with loops and arrays. ;)
foreach ([4 => range('A', 'Z'), 2 => range(0, 9)] as $n => $chars) {
for ($i=0; $i < $n; $i++) {
$otp[] = $chars[array_rand($chars)];
}
}
shuffle($otp);
$otp = implode('', $otp);

Answer 3

$seed = str_split('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
$seed2= str_split('0123456789');
$rand = [];
for($i=mt_rand(1,2);$i<=2;$i++){
shuffle($seed2);
$rand[]=$seed2[0];
}
while(count($rand)!=6){
shuffle($seed);
$rand[]=$seed[0];
}
shuffle($rand);
print $feedID = implode('',$rand);

Answer 4

you can use random() also to genarate the string with num + letters.LINK
function generateRandomString($length = 10) {
$characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charactersLength = strlen($characters);
$randomString = '';
for ($i = 0; $i < $length; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];
}
return $randomString;
}

Answer 5

Hope this help you
function generateRandomString($length = 10,$char_len=4,$numbre_len=2) {
$characters = '0123456789';
$characters2='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charactersLength = strlen($characters);
$charactersLength2 = strlen($characters);
$randomString = '';
for ($i = 0; $i <$char_len ; $i++) {
$randomString .= $characters2[rand(0, $charactersLength2 - 1)];
}
for ($i = 0; $i <$numbre_len ; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];
}
$shuffled = str_shuffle($randomString);
return $shuffled;
}
$length=7;
$char_len=6;
$numbre_len=1;
echo generateRandomString($length,$char_len,$numbre_len);
This function may help to generate dynamic random otp which you want.