Allow only 11 or 16 alphanumerical characters PHP

Question

How can I get a string that only contains maximum of 11 or 16 characters of a regex pattern ?

if(!preg_match("/^[a-zA-Z0-9]+$/", $str) == 1) {
        echo 'Invalid Characters';
    }
    echo 'Valid characters';

if Numeric, maximum length of 16 digits, If alpha-numeric, maximum length of 11 characters

Eg: Numeric = 0825551234

Eg: alpha-numeric = 1800House

Answer 1

Instead of outlining the rest of your requirements in comments you should update your question. Based on what I read, try this: /^[a-zA-Z0-9]{5,16}$/

Alpha-numeric, minimum 5 and maximum 16 characters repetition.

Answer 2

I am new to Regexp, but for me this is an answer for your question

if(preg_match("/^\d{1,16}$/", "12345678123456781") == 1)
{
echo "Numeric";
}
else if(preg_match("/^([\w\_]{1,11})$/", "qweqweqweqwe") == 1)
{
echo "Alphanumeric";
}
else
{
echo("some other stuff");
}

If you don't want to escape underscores, just replace second regexp with this /^(\\w{1,11})$/

Answer 3

if Numeric, maximum length of 16 digits, If alpha-numeric, maximum length of 11 characters

This should do it:

<?php

//$string="0123456789012345";/* 16 digits */
$string="012345abcde";       /* 11 alpha-numeric */

if( preg_match("/^[0-9]{1,16}$|^(?=.*[a-zA-Z])[a-zA-Z0-9]{1,11}$/", $string) )
{
  echo 'valid Characters';
}
else
{
  echo 'Invalid characters';
}

Quality Assurance: https://3v4l.org/1c2KD

Good luck!

Answer 4

        if(ctype_digit($this->smsSenderId) && strlen($this->smsSenderId) > 16){
         //'too long (maximum is 16 numeric characters)';
        }
        // alpha numeric can contain 11 characters
        else if(strlen($this->smsSenderId) > 11){
            //'too long (maximum is 11 alpha-numeric characters)';
        }
        else if(!preg_match("/^[0-9a-zA-Z]{4,11}$/", $this->smsSenderId) == 1){
            //'Invalid characters. Eg: 0825551234 or 1800House';
        }

Answer 5

You could do it without using a regex at all.

$strings = array('0825551234', '1800House', '111111111111111', 'aaaaaaaaaaa', '12!1adfas');
foreach($strings as $string){
echo "Testing for: $string";
if((is_numeric($string) && strlen($string) <=16) || (ctype_alnum($string) && strlen($string) <=11)) {
     echo ' true' . "\n";
} else {
     echo ' false' . "\n";
}
}

Output:

Testing for: 0825551234 true
Testing for: 1800House true
Testing for: 111111111111111 true
Testing for: aaaaaaaaaaa true
Testing for: 12!1adfas false

Or if you needed to regex:

$strings = array('0825551234', '1800House', '11122111111111111', 'aaaaaaaaaaa', '12!1adfas');
foreach($strings as $string){
echo "Testing for: $string";
if(preg_match('~^(\d{1,16}|[a-z0-9]{1,11})$~i', $string)) {
     echo ' true' . "\n";
} else {
     echo ' false' . "\n";
}
}

Regex101 demo: https://regex101.com/r/mN1aF8/1