php - Why isn't CodeIgniter taking certain variables as the third argument to form_dropdown()? -

my form set load values database (which i've passed via template engine) on first load, , posted values on subsequent loads if validation fails. instance, things work fine:

 $title = array(               'name'        => 'aboutme',               'id'          => 'aboutme',               'value'       => set_value('aboutme','{about_me}'),               'rows'        => '20',               'cols'        => '64'             ); 

but i'm stumbling on form_dropdown.

$ethnicity_array = array('please choose', 'asian', 'black', 'hispanic / latin',  'native american', 'pacific islander', 'southeast asian', 'white', 'mixed', 'other');  echo form_dropdown('ethnicity', $ethnicity_array,set_value('ethnicity','{ethnicity}')); 

it doesn't generate html mark choice selected.

even fails:

$var = set_value('ethnicity','{ethnicity}');  echo $var;     // verify has expected value, let's 7  echo form_dropdown('ethnicity', $ethnicity_array,$var); 

this fails -- is, doesn't generate proper html mark corresponding option selected:

echo form_dropdown('ethnicity',$ethnicity_array,(isset($_post['ethnicity']) ? $_post['ethnicity'] : $var)); 

but, works:

echo form_dropdown('ethnicity', $ethnicity_array,7); 

and this:

$var = 7;  echo form_dropdown('ethnicity', $ethnicity_array,$var); 

it seems it's sort of type casting issue, maybe it's fundamentally don't understand php.

update: may typecasting issue. trying this:

$var = "{ethnicity}";  echo var_dump($var);  $iv = intval($var);  echo "<div>iv:</div>";  echo var_dump($iv); 

yields:

string(15) "7" iv: int(0)

i have no clue why intval() return 0 string "7". i've looked @ other questions intval() here on stackoverflow , i'm more confused. if form_dropdown trying int conversion , it's failing, might problem.

you have pass set_value third paramenter code should this

echo form_dropdown('ethnicity', $ethnicity_array, set_value('ethnicity'));