CodeIgniter form_radio with set_value

Question

I am having a bit of trouble with my form and radio buttons, with input text I do this:

<?php echo form_input('lastname', set_value('lastname'), 'id=lastname'); ?>
<?php echo form_error('lastname'); ?>

and when the validation runs and that input field that is filled out gets the valued returned...what I am looking for is a way to do this with radio buttons

<tr><td><?php echo form_label('Gender: ', 'gender'); ?></td><td><?php echo form_label('Male', 'male') . form_radio('gender', 'M', '', 'id=male'); ?><br><?php echo form_label('Female', 'female') . form_radio('gender', 'F', '', 'id=female'); ?></td><td><?php echo form_error('gender'); ?></td></tr>

as you can see both my radio buttons have values already F or M.....how do I have the button that is selected returned selected?

Answer 1

From the user guide: https://www.codeigniter.com/user_guide/helpers/form_helper.html

form_radio()

This function is identical in all respects to the form_checkbox() function above except that is sets it as a "radio" type.

So reading further:

form_checkbox()

Lets you generate a checkbox field. Simple example:

echo form_checkbox('newsletter', 'accept', TRUE);

Would produce:

<input type="checkbox" name="newsletter" value="accept" checked="checked" />

The third parameter contains a boolean TRUE/FALSE to determine whether the box should be checked or not.

So in your case, it might be something like this:

// Pass boolean value to third param
// Example:
$radio_is_checked = $this->input->post('gender') === 'F';

echo form_radio('gender', 'F', $radio_is_checked, 'id=female');

Since set_radio() just returns a string checked="checked", you could wedge it in to the fourth paramter if you really wanted to but it makes for some ugly looking code:

echo form_radio('gender', 'F', NULL, 'id="female" '.set_radio('gender', 'F'));