Question

get_categories( string|array $args = '' )

Retrieve list of category objects.

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description

If you change the type to ‘link’ in the arguments, then the link categories will be returned instead. Also all categories will be updated to be backward compatible with pre-2.3 plugins and themes.

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参数

$args

(string|array) (Optional) Arguments to retrieve categories. See get_terms() for additional options.

• 'taxonomy'
  (string) Taxonomy to retrieve terms for. In this case, default 'category'.

Default value: ''

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返回值

(array) List of categories.

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源代码

File: wp-includes/category.php

function get_categories( $args = '' ) {
	$defaults = array( 'taxonomy' => 'category' );
	$args = wp_parse_args( $args, $defaults );

	$taxonomy = $args['taxonomy'];

	/**
	 * Filters the taxonomy used to retrieve terms when calling get_categories().
	 *
	 * @since 2.7.0
	 *
	 * @param string $taxonomy Taxonomy to retrieve terms from.
	 * @param array  $args     An array of arguments. See get_terms().
	 */
	$taxonomy = apply_filters( 'get_categories_taxonomy', $taxonomy, $args );

	// Back compat
	if ( isset($args['type']) && 'link' == $args['type'] ) {
		_deprecated_argument( __FUNCTION__, '3.0.0',
			/* translators: 1: "type => link", 2: "taxonomy => link_category" */
			sprintf( __( '%1$s is deprecated. Use %2$s instead.' ),
				'<code>type => link</code>',
				'<code>taxonomy => link_category</code>'
			)
		);
		$taxonomy = $args['taxonomy'] = 'link_category';
	}

	$categories = get_terms( $taxonomy, $args );

	if ( is_wp_error( $categories ) ) {
		$categories = array();
	} else {
		$categories = (array) $categories;
		foreach ( array_keys( $categories ) as $k ) {
			_make_cat_compat( $categories[ $k ] );
		}
	}

	return $categories;
}

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更新日志

Version	description
2.1.0	Introduced.

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相关函数

Uses

• wp-includes/l10n.php: __()
• wp-includes/category.php: _make_cat_compat()
• wp-includes/category.php: get_categories_taxonomy
• wp-includes/functions.php: _deprecated_argument()
• wp-includes/functions.php: wp_parse_args()
• wp-includes/taxonomy.php: get_terms()
• wp-includes/plugin.php: apply_filters()
• wp-includes/load.php: is_wp_error()
Show 3 more uses Hide more uses

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Used By

• wp-admin/includes/export.php: export_wp()
• wp-admin/includes/deprecated.php: wp_dropdown_cats()
• wp-includes/category-template.php: wp_list_categories()
• wp-includes/deprecated.php: get_links_list()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getCategories()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mt_getCategoryList()
• wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::wp_suggestCategories()
Show 2 more used by Hide more used by

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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: 3You must log in to vote on the helpfulness of this note Contributed by Codex

   List Categories and descriptions
   This example will list, in alphabetic order, all categories presented as links to the corresponding category archive. Each category description is listed after the category link.

   
   <?php
   $categories = get_categories( array(
   	'orderby' => 'name',
   	'order'   => 'ASC'
   ) );
   
   foreach( $categories as $category ) {
   	$category_link = sprintf( 
   		'<a href="%1$s" alt="%2$s">%3$s</a>',
   		esc_url( get_category_link( $category->term_id ) ),
   		esc_attr( sprintf( __( 'View all posts in %s', 'textdomain' ), $category->name ) ),
   		esc_html( $category->name )
   	);
   	
   	echo '<p>' . sprintf( esc_html__( 'Category: %s', 'textdomain' ), $category_link ) . '</p> ';
   	echo '<p>' . sprintf( esc_html__( 'description: %s', 'textdomain' ), $category->description ) . '</p>';
   	echo '<p>' . sprintf( esc_html__( 'Post Count: %s', 'textdomain' ), $category->count ) . '</p>';
   } 
   

Get only top level categories
To get the top level categories only, set parent value to zero. This example gets link and name of top level categories.

$categories = get_categories( array(
	'orderby' => 'name',
	'parent'  => 0
) );

foreach ( $categories as $category ) {
	printf( '<a href="%1$s">%2$s</a><br />',
		esc_url( get_category_link( $category->term_id ) ),
		esc_html( $category->name )
	);
}

Drop-down box as used in Parent category at post category page
This is the code used in the built-in category page.

wp_dropdown_categories( array(
	'hide_empty'       => 0,
	'name'             => 'category_parent',
	'orderby'          => 'name',
	'selected'         => $category->parent,
	'hierarchical'     => true,
	'show_option_none' => __('None')
) );

The slightly altered code below will grab all categories and display them with indent for a new level (child category). The select box will have name and id attribute values of ‘select_name’. This select element will not display a default “none” as the original code was used to attach a category as a child to another category (or none).

wp_dropdown_categories( array(
	'hide_empty'   => 0,
	'name'         => 'select_name',
	'id'           => 'select_name',
	'hierarchical' => true
) );

Drop-down Box
Here’s how to create a drop-down box of the subcategories of, say, a category that archives information on past events.
This mirrors the example of the drop-down example of wp_get_archives() which shows how to create a drop-down box for monthly archives.

Suppose the category whose subcategories you want to show is category 10, and that its category “nicename” is “archives”.

<select name="event-dropdown"> 
	<option value=""><?php echo esc_attr_e( 'Select Event', 'textdomain' ); ?></option> 
	<?php 
	$categories = get_categories( array( 'child_of' => 10 ) ); 
	foreach ( $categories as $category ) {
		printf( '<option value="%1$s">%2$s (%3$s)</option>',
			esc_attr( '/category/archives/' . $category->category_nicename ),
			esc_html( $category->cat_name ),
			esc_html( $category->category_count )
		);
  	}
 	?>
</select>