Question

Mid afternoon mental block. Simple PHP script to generate an HTML snippet. Will appreciate a second pair of eyes to spot what I’m doing wrong …

<?php $prevname = ''; ?>
<?php foreach($subcategories as $sub_category): ?>
    <?php $newname = $sub_category->getCategory()->getName(); ?>
    <?php $group_changed = strcmp($newname, $prevname); ?>
    <?php if ($group_changed): ?>
    <optgroup label="<?php echo $newname; ?>">
    <?php endif; ?>
        <option value="<?php echo $sub_category->getId(); ?>"><?php echo $sub_category; ?></option>
    <?php if ($group_changed): ?>
    </optgroup>
    <?php endif; ?>
<?php endforeach; ?>

[Edit]

Generated HTML looks like this:

<select>
    <optgroup label="Group1">
            <option value="1">Group1 Sub Item 1</option>
    </optgroup>
    <optgroup label="Group1">
            <option value="2">Group1 sub Item 2</option>
    </optgroup>
    <!-- and so on ...
</select>

instead of what I expected:

<select>
    <optgroup label="Group1">
            <option value="1">Group1 Sub Item 1</option>
            <option value="2">Group1 sub Item 2</option>
    </optgroup>
    <optgroup label="Group2">
            <option value="1">Group2 Sub Item 1</option>
            <option value="2">Group2 sub Item 2</option>
    </optgroup>
    <!-- and so on ...
</select>

Answer 1

<?php $group_changed = (strcmp($newname, $prevname) != 0) ; ?>

And you are not assigning $prevname to the $newname.

Additionally, the optgroup should be closed not in the same iteration, but on next optgroup name change. The code should look something like this:

<?php $prevname = ''; $group_opened = false; ?>
<?php foreach($subcategories as $sub_category): ?>
    <?php $newname = $sub_category->getCategory()->getName(); ?>
    <?php $group_changed = (strcmp($newname, $prevname)!=0) ; ?>
    <?php if ($group_changed): $prevname = $newname;?>
           <?php if ($group_opened):?>
             </optgroup>
           <?endif; ?>
    <optgroup label="<?php echo $newname; ?>">
     <?php $group_opened = true; ?>
    <?php endif; ?>
        <option value="<?php echo $sub_category->getId() ?>"><?php echo $sub_category; ?></option>
<?php endforeach; ?>