Went a different route.
// Hook to save_post action
add_action('save_post', 'update_number_field');
function update_number_field($post_id) {
// Check if it's an autosave
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) {
return;
}
// Check if the user has permission to edit the post
if (!current_user_can('edit_post', $post_id)) {
return;
}
// Check if the post type is the one you want to target (e.g., 'post' or 'page')
$post_type = get_post_type($post_id);
if ($post_type != 'team') {
return;
}
// Get the values of the checkbox field
$checkbox_values = get_post_meta($post_id, 'state_title_years_won', true);
// Calculate the number of checked checkboxes
$number_field_value = is_array($checkbox_values) ? count($checkbox_values) : 0;
// Update the number field
update_post_meta($post_id, 'total_state_championships_won', $number_field_value);
}