Here is another great WordPress function to test if you are in a subcategory or the actual parent category and if so return true. This function is pretty much identical in concept to the is_page_or_sub() function I released previously. However, it just tests categories and not pages. Also, the code is significantly different since there are a few more available pre existing function we can build upon here.
For example, the cat_is_ancestor_of() function comes in really handy and does a lot of the heavy lifting for this simple but very powerful function. I use this very function to build complex category based navigation and test for active states and use the appropriate CSS in the change we’re actually in one of the categories we’re testing for. If you have question feel free to ask by commenting below and enjoy mastering WordPress!
The Function
1 2 3 4 5 6 7 8 9 | // If is category or subcategory of $cat_id if (!function_exists('is_category_or_sub')) { function is_category_or_sub($cat_id = 0) { foreach (get_the_category() as $cat) { if ($cat_id == $cat->cat_ID || cat_is_ancestor_of($cat_id, $cat)) return true; } return false; } } |
Sample Usage
1 2 3 4 5 | if (is_category_or_sub(1)) { DISPLAY SOMETHING } else { DISPLAY SOMETHING DIFFERENT } |
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Disclaimer
Valen Designs grants you a nonexclusive copyright license to use all programming code examples from which you can generate similar function tailored to your own specific needs.
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Comments
“Hi again.
It works fine if I test for one category. I have between 4-6 categories on each page and I would like to test for all of them in one statement. ( If this post belongs to cat 13 or 14 or…or 17, then return true)
I tried in a few different ways without success. Is it possible?
I really appreciate you taking the time!!!”
@chris Jangelov: You can test multiple categories at one time no problem, that is what this function does. First are all these categories children of one parent caregory? If so you just need to pass in the id of the parent category and the function will return true.
For example,
if (is_category_or_sub(13) { echo ’something’; }
However, if you are testing just random categories and not parent child relationships all you need to do is:
if (in_category(13) || in_category(15)) { echo ’something’; }
hi
does it work also with category-slugs?
thank you
Derek,
You made my day. I had no idea that I could test for category outside the loop so I never tried that. Went for pageID instead.
As you supposed it was enough with the in_category function.
Thank you very much for your help. May your life be long and happy!
Always glad to help and good luck with your project.
Works great, thank you
Awesome, glad to hear it.
Thanks for this function. Works great! Do you have a “donate” button? Would like to show my appreciation.
Sure you can donate using the button I added above. Glad it was of use to you!
Thanks heaps exactly what I was looking for!
hi!
sorry i don’t very good in php but your code don’t work good on my site.
i have a category and a subcategory and with your code i can see if i am in category or subcategory true?
i have put this code:
// If is category or subcategory of $cat_id
if (!function_exists(‘is_category_or_sub’)) {
function is_category_or_sub($cat_id = 0) {
foreach (get_the_category() as $cat) {
if ($cat_id == $cat->cat_ID || cat_is_ancestor_of($cat_id, $cat)) return true;
}
return false;
}
}
if (is_category_or_sub(1)) {
echo “DISPLAY 1″;
} else {
echo “DISPLAY 2″;
}
in page archive.php
but i see string “DISPLAY 2″ in booth category and subcategory why?
i have put this code before in archive page.
Can you help me please?where i wrong?
regard erwin
ps sorry my bad english :P
ok i know!
i have add code:
$this_category = get_category($cat);
and modifie the function “is_category_or_sub” with parameter $this_category and this work!!
thx a lot!
:)
good blog
regard
erwin
Trau, for starters you should be putting the function in your functions.php and not in your theme file.
Second, I use this function on almost every site I’ve ever built and it has always worked fine. I’m not sure why you are having difficulty but there is no reason I can think of that you would need to edit the original function.
I’m glad you got it to work anyhow.
HI Derek,
I think Trau’s problem (emphasis on i*I think*, I probably should try it first) might have to do with the categories the current post was assigned to. What I mean is.. when that post was added, it could have been assigned both the parent and child category in the Categories box ( via checking both the parent and child boxes)
Unless that’s the proper way of doing that?
It can’t be, right? However, for example, when if setup my permalink structure as so:
/%category%/%postname%/
I end up with the permalink of my child category posts showing only the parent category while /%category%/ is supposed generate the nested directory for the sub category.
-C
To clarify, the function says return true if parent OR child. So, it doesn’t matter if you have both of them checked off or not.
Hi Derek,
Thanks for providing this solution.
You should submit it to WP because it is a valuable and quite used function. For me, you saved the day !!!
Kudos!
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