Question

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

Retrieve the list of categories for a post.

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description

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

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参数

$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()

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返回值

(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.

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源代码

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;
}

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更新日志

Version	description
2.1.0	Introduced.

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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.

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相关函数

Uses

• wp-includes/functions.php: wp_parse_args()
• wp-includes/taxonomy.php: wp_get_object_terms()

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Used By

• wp-admin/includes/post.php: bulk_edit_posts()
• wp-includes/deprecated.php: wp_get_post_cats()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mt_getPostCategories()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mt_publishPost()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getPost()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getRecentPosts()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::blogger_getPost()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::blogger_getRecentPosts()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::_prepare_page()
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User Contributed Notes

1. Skip to note content You must log in to vote on the helpfulness of this noteVote results for this note: 5You must log in to vote on the helpfulness of this note Contributed by Codex

   The example below shows how categories are retrieved, and then additional information is retrieved for each category.

   
   $post_categories = wp_get_post_categories( $post_id );
   $cats = array();
   	
   foreach($post_categories as $c){
   	$cat = get_category( $c );
   	$cats[] = array( 'name' => $cat->name, 'slug' => $cat->slug );
   }