One line PHP code to remove characters except numbers and letters

I found this few lines of PHP script useful to sanitize user input, it removes characters except numbers and letters:

$clean_code = preg_replace('/[^\w]/', '', $string);

Or this one:

$clean_code = preg_replace('/[^a-zA-Z0-9]/', '', $string);

Original post is here:

How to send POST request to another website from a PHP script

Let’s say we have a website like and there is an input form, but we don’t want to submit that form from that website, instead we send POST request to that page from another website. Here is a handy PHP script to do so:


$url = '';
$data = array('key1' => 'value1', 'key2' => 'vaue2');

$options = array(
    'http' => array(
        'header'  => "Content-type: application/x-www-form-urlencoded\r\n",
        'method'  => 'POST',
        'content' => http_build_query($data)
$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);
if ($result === FALSE) { /* Handle error */ }



How to resize QR Code image generated by phpqrcode library

In this tutorial I will show you how to modify the phpqrcode library to generate more bigger and larger QR Code image.

By default if we generate a QR Code of short text or string, we will get a small QR Code image approximately less than 100 pixels. But we can multiply by any number we like.