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wp_get_post_categories( int $post_id, array $args = array() )

Retrieve the list of categories for a post.

Description

Compatibility layer for themes and plugins. Also an easy layer of abstraction away from the complexity of the taxonomy layer.

See also

Parameters

$post_id

(int) (Optional) The Post ID. Does not default to the ID of the global $post. Default 0.

$args

(array) (Optional) Category query parameters. See WP_Term_Query::__construct() for supported arguments.

Default value: array()

Return

(array|WP_Error) List of categories. If the $fields argument passed via $args is 'all' or 'all_with_object_id', an array of WP_Term objects will be returned. If $fields is 'ids', an array of category IDs. If $fields is 'names', an array of category names. WP_Error object if 'category' taxonomy doesn't exist.

More Information

The results from wp_get_post_categories() aren’t cached which will result in a database call being made every time this function is called. Use this function with care. For performance, functions like get_the_category() should be used to return categories attached to a post.

Source

File: wp-includes/post.php 

function wp_get_post_categories( $post_id = 0, $args = array() ) {
	$post_id = (int) $post_id;

	$defaults = array( 'fields' => 'ids' );
	$args     = wp_parse_args( $args, $defaults );

	$cats = wp_get_object_terms( $post_id, 'category', $args );
	return $cats;
}

Uses

Uses Description
wp-includes/functions.php: wp_parse_args()

Merge user defined arguments into defaults array.
wp-includes/taxonomy.php: wp_get_object_terms()

Retrieves the terms associated with the given object(s), in the supplied taxonomies.

Used By

Used By Description
wp-admin/includes/post.php: bulk_edit_posts()

Process the post data for the bulk editing of posts.
wp-includes/deprecated.php: wp_get_post_cats()

Retrieves a list of post categories.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mt_getPostCategories()

Retrieve post categories.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mt_publishPost()

Sets a post’s publish status to ‘publish’.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getPost()

Retrieve post.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getRecentPosts()

Retrieve list of recent posts.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::blogger_getPost()

Retrieve post.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::blogger_getRecentPosts()

Retrieve list of recent posts.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::_prepare_page()

Prepares page data for return in an XML-RPC object.

Changelog

Version Description
2.1.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/wp_get_post_categories?replytocom=493