codeigniter中select字段选项的set_value

Question

I really wonder to set_select for select field in codeigniter. I already try for many ways but it doesn't work.

I have an variable here $date_dossier = date_parse($patient['patient_date_dossier']); but it doesn't defined the function below:

<?php echo form_error('dossier_day') ?>
<?php
$option_day = array(
    '01' => '01', '02' => '02', '03' => '03', '04' => '04', '05' => '05', '06' => '06', '07' => '07',
    '08' => '08', '09' => '09', '10' => '10', '11' => '11', '12' => '12', '13' => '13', '14' => '14',
    '15' => '15', '16' => '16', '17' => '17', '18' => '18', '19' => '19', '20' => '20', '21' => '21',
    '22' => '22', '23' => '23', '24' => '24', '25' => '25', '26' => '26', '27' => '27',
    '28' => '28', '29' => '29', '30' => '30', '31' => '31'
);
echo'<select name="dossier_day" class="form" id="day">';
for ($a = 1; $a <= 31; $a++) {
    ?>
<option value="<?php echo $a < 10 ? '0' . $a : $a ?>"> 
  <?php if($a==$date_dossier['day']){
    echo 'selected='.'"'.$a.'"';
  }?>
     <?php echo $a < 10 ? '0' . $a : $a ?></option>
    <?php
}
echo'</select>';  echo '<span style="color:red">'.form_error('dossier_day').'</span>'
?>

Answer 1

<?php 

echo form_error('dossier_day');

$option_day = array(
    '01' => '01', '02' => '02', '03' => '03', '04' => '04', '05' => '05', '06' => '06', '07' => '07',
    '08' => '08', '09' => '09', '10' => '10', '11' => '11', '12' => '12', '13' => '13', '14' => '14',
    '15' => '15', '16' => '16', '17' => '17', '18' => '18', '19' => '19', '20' => '20', '21' => '21',
    '22' => '22', '23' => '23', '24' => '24', '25' => '25', '26' => '26', '27' => '27',
    '28' => '28', '29' => '29', '30' => '30', '31' => '31'
);

$d_dossier = $date_dossier['day'];
if (intval($d_dossier) < 10) $d_dossier = sprintf('%02d', $d_dossier);
$extra = array("class" => "form" "id" => "day");

echo form_dropdown('dossier_day', $options_day, $d_dossier, $extra);
echo '<span style="color:red">'.form_error('dossier_day').'</span>';

?>