Setting the default value of an entity form radio button using hook_form_FORMID_alter

Question

I have written a custom Drupal 7 module which needs to set the value of a radio button of an entityform based on a value queried from the database. I have tested hook and it is working as i am able to set a text field with in the form using:

$form['field_sem_submitter_id']['und'][0]['value']['#value'] = $user->uid;

I have tried, to no avail, to set the radio using the following and various other suggestions:

$form['field_sem_pledge_currency']['und'][0]['value']['#value'] = '2';
$form['field_sem_pledge_currency']['und'][0]['value']['#value'] = 'currency_bitcoin';
v$form['field_sem_pledge_currency']['#default_value'] = 'currency_bitcoin';

I have searched and tried numerous other suggestions on the web with no success. Any suggestions greatly appreciated.

Answer 1

Can u please try below code:

$form['field_sem_pledge_currency']['und'][0]['#default_value']['value'] = 'currency_bitcoin';

Answer 2

I was able to set the default using:

$form['field_sem_pledge_currency']['und']['#default_value'] = 'currency_bitcoin';