Submitting form with an Email Confirm field results in fatal PHP error because core email validator doesn't handle an array in #values array key [#3284625] | Drupal.org
php - can't save new data, and Array to string conversion? - Stack Overflow
String in PHP | Four Different Types of String Declaration in PHP
Important PHP String Functions. A string is group of characters. It is… | by Shankar Babu Acharya | Medium
Unexpected T_STRING | AwardSpace.com
trim() in PHP | Tree Types of trim() in PHP You Need To Know