checkboxes only appearing for first and last options - php

Question

What the code does below is it retrieves individual options in a full option type. So for example if $option is A-D, then by using the explode, it will be able to display each individual option to output A B C D.
Now In this example I want A B C D to each have it's own checkbox. But with the code below it is just creating checkbox for A and D, the first and last options when it should do it for A, B, C, D. How can this be done?
function ExpandOptionType($option) {
$options = explode('-', $option);
foreach($options as $indivOption) {
echo '<p><input type="checkbox" name="options[]" id="option-' . $indivOption . '" value="' . $indivOption . '" /><label for="option-' . $indivOption . '">' . $indivOption . '</label></p>';
}
if(count($options) > 1) {
$start = array_shift($options);
$end = array_shift($options);
do {
$options[] = $start;
}while(++$start <= $end);
}
else{
$options = explode(' or ', $option);
}
return implode(" ", $options);
}

Answer 1

function ExpandOptionType($option) {
$options = explode('-', $option);
if(count($options) > 1) {
$start = array_shift($options);
$end = array_shift($options);
do {
$options[] = $start;
}while(++$start <= $end);
}
else{
$options = explode(' or ', $option);
}
foreach($options as $indivOption) {
echo '<p><input type="checkbox" name="options[]" id="option-' . $indivOption . '" value="' . $indivOption . '" /><label for="option-' . $indivOption . '">' . $indivOption . '</label></p>';
}
return implode(" ", $options);
}
This way you first change the options array and then create the checkboxes.

Answer 2

Well, I am not quite sure what the if-else in your function does, but is this what you are thinking about?
<?php foreach (range('A','D') as $letter): ?>
<p>
<input type="checkbox" name="options[]" id="option-<?php echo $letter ?>" value="<?php echo $letter ?>" />
<label for="option-<?php echo $letter ?>"><?php echo $letter ?></label>
</p>
<?php endforeach ?>
Or, in a function:
function ExpandOptionType($from, $to) {
$output = '';
$range = range($from, $to);
foreach ($range as $letter) {
$output .= '<p>';
$output .= "<input type=\"checkbox\" name=\"options[]\" id=\"option-{$letter}\" value=\"{$letter}\" />";
$output .= "<label for=\"option-{$letter}\">{$letter}</label>";
$output .= '</p>';
}
return $output;
}
echo ExpandOptionType('A', 'D');