How to manipulate submitted data in Symfony 2 Forms Framework?

  bind, forms, php, symfony

I’m learning how to make up websites using frameworks. my Mentor chosen Symfony 2 for me to start.
But i’ve a recuring error when using forms, (for more details when I use the bind() method) the error is

Warning: count(): Parameter must be an array or an object that implements Countable in C:wamp64wwwSymfonyvendorsymfonysymfonysrcSymfonyComponentValidatorValidatorRecursiveContextualValidator.php line 731

This error also apear when trying to submit the form to configure Symfony.
So I don’t think that the problem comes from my code. How to manipurate the submitted data?

i use Symfony 2.5.1
my php version is 7.2.18
i realy need help! im looking for help since two weeks

Source: Symfony Questions