Categories in WordPress

In this post, we’ll see how to create categories in WordPress, subcategories, and what the code is that defines one or more categories in a template.

Putting our posts into categories is a good way to group our posts and then have them displayed.

Categories apply to posts, which is why creating a category is found in the Posts tab.

On the image before we can see how to create a new category and how to put or not this one as subcategory, you may put a category as subcategory of other specifing its parent(Parent Category).

Observe that in this post i was created a category called “php” with slug “php-slug” ¿What will use wordpress the slug or the name in a URL?

WordPress will use the slug instead of the name in the url

Category Template

We can create a page for categories, in an older post we see the loop and how to create a simple index.php now we’re going to create a category.php file, remember if wordpress do not have a category.php it will load the index file instead, this is explained in WordPress template hirarchy.

I going to take what we do on “the loop” post and i will change it slightly, this code as is actually works is the code im using it to show you the slug example.

<?php
/**this is a basic wordpress loop */

get_header();

if(is_category()):
    if ( have_posts() ) {

        // Load posts loop.
        while ( have_posts() ) {
            the_post();?>
            <a href="<?php the_permalink();?>">
            <h1><?php the_title();?></h1>
            </a>
            <?php the_content();
        }
    }
    else{
        echo "no post to be showed";
    }
endif;
get_footer();

In this example I added “is category” function that checks if is a category instead of do the loop in vain.

Customize your Category

As I write in WordPress template hierarchy, categories can be customized using a slug or an id being the files in the following way:

• category-$slug.php
• category-$ID.php

Let’s create a file with slug for example think that you are creating a site of recipes, the category that I want would it be desserts, thus I will put that name as slug.

Now we have to create that file “category-desserts.php”, and now I’m going to copy and change a little what I have in category.php.

I’m going to put this image when the category is desserts, to notice the difference between a normal category and this one.

Then you have to enter in category/postres in my case my project is called test so my URL will be:

http://localhost/test/category/postres/

<style>
.header_postre{
    background:url('https://image.flaticon.com/icons/png/512/1477/1477733.png') no-repeat;
    background-size: 50px 50px;
}
h1{
    margin-left:50px;
}

<?php
/**this is a basic wordpress loop */

get_header();

if(is_category("postres")):
    echo "<div class='header_postre'><h1>";
    echo "Postres";
echo "</h1></div>";
    if ( have_posts() ) {

        // Load posts loop.
        while ( have_posts() ) {
            the_post();?>
            <a href="<?php the_permalink();?>">
            <h1><?php the_title();?>
            </a>
            <?php the_content();
        }
    }
    else{
        echo "no post to be showed";
    }
endif;
get_footer();

Functions that you can use in categories

Check if is the category assigned to the variable $category, by default the value is “”, is_category permit us using it without parameter when we are in a category page and check if is a category

Obtain all the categories that you added on WordPress via post > categories

Returns an array of objects WP_Term

You may obtain the category id with the following code:

$category = get_the_category();
echo $category[0]->cat_ID;

To obtain the category name we can use get_cat_name, we only need to pass the category id as a parameter

Also, we can get the category name with this one too, single_cat_title(“”,false) this does not print the name of the category on the screen, only obtain it, so you can obtain it and use it in a variable.