Codeigniter - Form validation converting post variables from Array to "Array" string

I am building an HTML form with a set of checkboxes for selecting multiple categories using this format:

<input type="checkbox" name="category[]" />

So, when I post and print_r($_POST) to view the variable and values I get:

Array
(
    [27] => on
    [28] => on
    [29] => on
)

Once I run $this->form_valida开发者_JAVA技巧tion->run(); the categories array becomes "Array" as a string. I believe I have narrowed it down to "prep_for_form" function in the system/libraries/Form_validation.php file, but it seems like the recursive function is working correctly.

Thank you in advance.

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I figured it out. When using the $this->form_validation->set_rules() method, in the validation rules (third parameter) I set it to trim|required. I guess the trim function treats the actual Array like a string "Array" and trims the word. I simply removed the "trim" rule from my validation rules. e.g.

$this->form_validation->set_rules('category', 'categories', 'trim|required');

// when parsing an array (set of checkboxes, radio buttons, etc.) 
// - remove the "trim" validation
$this->form_validation->set_rules('category', 'categories', 'required');

I hope others find this useful.

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That solution did not work for me, but there is a fix listed here that did: http://ellislab.com/forums/viewthread/156497/