How to use get_the_categories filter in WordPress

get_the_categories filter

Filters the array of categories to return for a post.

To use get_the_categories filter, first, you have to register it using add_filter. You can write this code into functions.php of your activated theme or in a custom WordPress Plugin.

At WePlugins, we always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function modify_get_the_categories_defaults which takes 2 parameters and we registered using add_filter. The first parameter get_the_categories is the name of the hook, the second parameter modify_get_the_categories_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times, and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook so you can use remove_filter to remove get_the_categories filter.

Parameters

Below are the 2 parameters required to use this hook.

• $categories: (WP_Term[]) An array of categories to return for the post.
• $post_id: (int|false) ID of the post.

Live Example

Below is an example of how you can use this hook.

Example 1: Modify Categories

This example demonstrates how to modify the categories array for a post.

	function weplugins_modify_get_the_categories_defaults($categories, $post_id) {
		// Update the $categories variable according to your website requirements and return this variable.
		// You can modify the $categories variable conditionally too if you want.
		return $categories;
	}
	// Add the filter
	add_filter("get_the_categories", "weplugins_modify_get_the_categories_defaults", 10, 2);
	

Example 2: Remove Specific Categories for a Post

This example shows how to remove certain categories on a post loop for a specific post.

	function weplugins_remove_selected_categories($categories) {
		if (5 == get_the_ID()) { // Check if it is a specific post.
			$categories_to_remove = array('cat-slug-a');
			$categories = array_diff($categories, $categories_to_remove);
		}
		return $categories;
	}
	// Add the filter
	add_filter("get_the_categories", "weplugins_remove_selected_categories");
	

Example 3: Removing a Hook Callback

To remove a hook callback, use the example below.

	remove_filter("get_the_categories", "weplugins_modify_get_the_categories_defaults", 10, 2);
	

Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.