I currently have debug mode enabled in wp-config.php. I'm trying to loop through all the products in a certain category on my store.

$args = array(
    'post_type' => 'product',
    'product_cat' => 'scotch-whisky',
    'orderby' => 'title',
    'posts_per_page' => -1,
    'order' => 'ASC'

$loop = new WP_Query( $args );

I am then attempting to loop through the products and get a list of brand names. There might be five products with the brand name "Apple", however I am curating a list of brands so I only want "Apple" to appear once in the array.

To do that I loop through the products and check if the brand name is in my list, if it is I skip it, if not I add it to my list.


$distilleries = Array();

while ( $loop->have_posts() ) : $loop->the_post();
    $attr = wc_get_product_terms(get_the_id(), 'pa_distillery');
    if (
        in_array($attr[0], $distilleries) === false &&
        strlen($attr[0]) !== 0
    ) {

        array_push($distilleries, $attr[0]);


                <a href="<?php echo get_site_url(); ?>/product-category/scotch-whisky/?filter_distillery=<?php echo strtolower($attr[0]); ?>">
                    <?php echo $attr[0]; ?>





The problem appears on some iterations where I try to access $attr[0] in the if statement and get the following error:

Notice: Undefined offset: 0 in /home/www.something.com/123/public_html/wp-content/plugins/brand-list/list.php on line 87

Notice: Undefined offset: 0 in /home/www.something.com/123/public_html/wp-content/plugins/brand-list/list.php on line 88

I run a var dump on $attr[0] and $attr[0] is NULL. How can I stop this error from appearing or is there even anything I need to do or worry about?

Many thanks,


  • 1
    You need to check if $attr[0] exists using isset(), or that $attr isn’t empty(), before attempting to use $attr[0], even in an if condition. – Jacob Peattie Oct 3 '18 at 18:04
  • Yes this solved the notification. Amazing! Thanks for the quick help!! – Jethro Hazelhurst Oct 3 '18 at 23:33

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