You can retrieve the topmost parent category id of a post by using this three-line code.

$category = get_the_category();
$cat = get_category($category[0]->term_id);
$parent_catid = $cat->category_parent;

The first line will get the category of the current post.

techrounder-default

The second line will create an object of the first category of the post.

Here the id of the first category can be get by using the code $category[0]->term_id

Finally, you can retrieve the parent category id by using

$parent_catid = $cat->category_parent;

Now parent category id will be in the variable $parent_catid

Categorized in:

Webtips,