Validating Radio button's in a webform

[updesign]

I have a web form and want to add additional fields in it that must be answered by selection a radio button option. If anyone could help would be very grateful of any assistance. Below is part of the script so far.

"name" => array(
"regex" => "/^([a-zA-Z '-]+)$/",
"error" => "error message here",
),

[devinemke]

a simple example:

<form action="" method="post">
please select:<br>
<input type="radio" name="number" value="1">1<br>
<input type="radio" name="number" value="2">2<br>
<input type="radio" name="number" value="3">3<br>
<input type="radio" name="number" value="4">4<br>
<input type="radio" name="number" value="5">5<br>
<input type="submit" name="submit" value="submit">
</form>

<?php
if (isset($_POST['submit']))
{
	if (isset($_POST['number']))
	{
		echo 'you selected ' . $_POST['number'];
	}
	else
	{
		echo 'ERROR: you did not make a selection';
	}
}
?>