只需将数据分成3组，然后添加嵌套循环即可迭代每个组的数据.

Just chunk your data into sets of 3 and add a nested loop to iterate each set's data.

foreach (array_chunk($products, 3) as $set) {
    echo '<div class="row">';
        foreach ($set as $product) {
            echo '<div class="col-lg-4 col-md-4">';
                ...
            echo '</div>';
        }
   echo '</div>';
}