Checking hierarchical taxonomy

You’re calling cat_is_ancestor_of() wrong. Both values passed to that function have to be either a taxonomy term object or an integer ID. A string like ‘Animals’ is invalid and won’t work.

To see how it works, just check the codex page. Assuming that the main parent ID that you want to check os ‘1’, you’d just use this:

if( cat_is_ancestor_of( 1, get_query_var( 'cat' ))) {
    // Do stuff...
} // if ()

This is exactly why I’m using integers, just as you said for the usual categories.

I just thought this would better illustrate my question, which probably was not good idea.

The question though remains unanswered.

What about the custom hierarchical taxonomy?

I did miss that part, sorry. Too busy looking at the function to see what was going on.

For costom taxonomies. you can use term_is_ancestor_of(). It’s almost the same, but you tell it what taxonomy you’re referring to.

https://codex.www.ads-software.com/Function_Reference/term_is_ancestor_of

I had a look at that before and it didn’t work.

I think the reason for this is that it’s not about the terms – there is a single term in my case -> advert

The name of custom taxonomy is advert_category.

( term_is_ancestor_of(380, $term, 'advert_category')

380 – ID of the parent taxonomy category.
Didn’t work.

Just on the off chance… Are you 100% Sure that the term that you’re using and the one with the ID of 380 are both ‘advert_category’ terms? I know that it seems like a silly question, but I’ve gotten things easier then that wrong before.

If they are both correct, I’d try digging into the code for that function to see what it does, and see if you can find out why it’s failing. That is the function to use, so there’s got to be a reason for it failing if it’s not meant to.

Well it’s definitely not working irrespective of the theme I use.

Custom hierarchical taxonomy: Family
1st Parent term: Jacksons (id=1)
Child term: Mother
Child term: Father

The following code placed in archive.php (TwentySeventeen) returns nothing when visiting the actual archives.

<?php
if ( term_is_ancestor_of( 1, $term, 'family') ) : ?>
    <p>Jacksons</p>
<?php endif; ?>

What’s working
is_tax( 'family', 1 );

But that means this would need to be repeated for all of the child terms >50.

Umm, isn’t proper use of an ancestor_of function in whatever form sorta off topic? ??

You want the invert of that, yes? Does this term’s ancestor ID == 1? Every term object has a parent ID field. Get the term of that ID. Is that term’s ID == 1? If yes, there’s your answer. If no, does ID == 0? If not, rinse and repeat. If yes, you’ve reached the top level term and there was no match.

^^ code that

I feel the irony, but I could not get your actual answer.

I want to show the same message when visiting each and every archive of the children term of the parent term with the ID = 1, just as I wrote earlier.

Are you implying I should use something else?

I’ve just done some tests, and term_is_ancestor_of() works exactly as it’s meant to. My example…

Create taxonomy:

register_taxonomy ('ancestry', 'page', array (
    'label' => 'Ancestry',
    'hierarchical' => true
));

Set up terms for the ‘ancestry’ taxonomy (listed with ID’s):

19 -    First Level
20 -        Second Level
22 -            Third Level
21 -        Second Level 2
23 -    First Level 2

Code to check function:

echo "<p>Second Level is ancestor of First Level - '".term_is_ancestor_of (19, 20, 'ancestry')."'</p>";
echo "<p>Third Level is ancestor of First Level - '".term_is_ancestor_of (19, 22, 'ancestry')."'</p>";
echo "<p>Third Level is ancestor of First Level 2 - '".term_is_ancestor_of (23, 22, 'ancestry')."'</p>";

Results:

Second Level is ancestor of First Level - '1'
Third Level is ancestor of First Level - '1'
Third Level is ancestor of First Level 2 - ''

So the first two checks come back as true, and the third is false, which is exactly what the results are supposed to be.

From this, all that I can think of is that either you’ve got the ID’s the wrong way around, or that your taxonomy isn’t set up as hierachical.

Thanks for the response, @catacaustic.

Could you please edit the code to not include the child term exactly like in the example in documentation?

If you have to use $term, then I’d suggest something like this, to test what you are ctualyl using for $term.

echo "<p>Term is '".$term."'</p>";
echo "<p>Checking term:  '".term_is_ancestor_of (19, $term, 'ancestry')."'</p>";

Thanks for the effort @catacaustic ??

What I am using the term_is_ancestor_of for is exact replication of the example provided in codex:

The code snip below checks to see if the term called ‘Music’ (ID 4) for the taxonmy ‘Sound’ is being processed, and if so, presents a wp_nav_menu for the Music archive page, and any subterms of Music (e.g. jazz, classical.)

It is this part that is my actual goal:

and any subterms of Music (e.g. jazz, classical.)

<?php 
  if (term_is_ancestor_of(4, $term, 'sound') or is_term(4, 'sound')):  ?>
  <div id="music_subnav_menu" class="subnav_menu">
    <?php wp_nav_menu( array('menu' => 'Music' )); ?>
  </div>
<? endif; ?>

which is just not working.

• This reply was modified 6 years, 5 months ago by chinatownlee.
• This reply was modified 6 years, 5 months ago by chinatownlee.

Do you have a custom taxonomy of ‘sound’ set up with a parent that has the ID of 4? If not, it will fail because that’s what it’s asking for. You can’t just cut-and-past that. You need to make sure that you have the correct values being passed in to that function.

Whenever I’m visiting child terms of 448 and 451 I see both messages ‘Jacksons’ and ‘Watsons’ and as I now understand this works as intended.

if (term_is_ancestor_of(448, $term, 'family') or is_term(448, 'family')) {
echo '<p>Jacksons</p>'; }
if (term_is_ancestor_of(451, $term, 'family') or is_term(451, 'family')) {
echo '<p>Watsons</p>'; }

I a have a bunch of different parent terms with child terms and I hoped I could use this function for delivering conditional content in a way I wanted.

Any advice on how could I achieve the goal of displaying only the ‘Watsons’ message when visiting any of the child terms of Parent ID 451?

• This reply was modified 6 years, 5 months ago by chinatownlee.
• This reply was modified 6 years, 5 months ago by chinatownlee.

Let’s see if I can comment this time without getting my thinking backwards ??

Don’t bother with a series of if () conditional logic. Would the term ID 451’s name be ‘Watsons’ by any chance? If not, the string could be stored as term meta. Then if you got any term’s ancestors with get_ancestors(), the last object in the returned array is the top level term. Its name is in that object, or get the stored meta by term ID. Get it and output the value. Then a couple lines of code will work for any number of top level terms and their children, and you do not need to add to your code if additional lines of descendants were to be added.