wp_dropdown_categories( array|string $args = '' ): string

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$argsarray|stringoptional

Array or string of arguments to generate a categories drop-down element. See WP_Term_Query::__construct() for information on additional accepted arguments.Default: ''

• $show_option_allstringdefault: empty

  Text to display for showing all categories.

• $show_option_nonestringdefault: empty

  Text to display for showing no categories.

• $option_none_valuestringdefault: empty

  Value to use when no category is selected.

• $orderbystringdefault: 'id' (term_id)

  Which column to use for ordering categories. See get_terms() for a list of accepted values.

• $pad_countsbooldefault: false

  See get_terms() for an argument description.

• $show_countbool|intdefault: 0

  Whether to include post counts. Accepts 0, 1, or their bool equivalents.

• $echobool|intdefault: 1

  Whether to echo or return the generated markup. Accepts 0, 1, or their bool equivalents.

• $hierarchicalbool|intdefault: 0

  Whether to traverse the taxonomy hierarchy. Accepts 0, 1, or their bool equivalents.

• $depthintdefault: 0

  Maximum depth.

• $tab_indexintdefault: 0 (no tabindex)

  Tab index for the select element.

• $namestringdefault: 'cat'

  Value for the 'name' attribute of the select element.

• $idstring

  Value for the 'id' attribute of the select element. Defaults to the value of $name.

• $classstringdefault: 'postform'

  Value for the 'class' attribute of the select element.

• $selectedint|stringdefault: 0

  Value of the option that should be selected.

• $value_fieldstringdefault: 'term_id'

  Term field that should be used to populate the 'value' attribute of the option elements. Accepts any valid term field: 'term_id', 'name', 'slug', 'term_group', 'term_taxonomy_id', 'taxonomy', 'description', 'parent', 'count'.

• $taxonomystring|arraydefault: 'category'

  Name of the taxonomy or taxonomies to retrieve.

• $hide_if_emptybooldefault: false (create select element even if no categories are found)

  True to skip generating markup if no categories are found.

• $requiredbooldefault: false

  Whether the <select> element should have the HTML5 'required' attribute.

• $walkerWalkerdefault: empty which results in a Walker_CategoryDropdown instance being used

  Walker object to use to build the output.

• $aria_describedbystringdefault: empty string

  The 'id' of an element that contains descriptive text for the select.

Return value

string

HTML dropdown list of categories.

Performance profile

How much work a call to wp_dropdown_categories() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_terms().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

74–180

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 225.

Plugin surface

2 hooks

Third-party callbacks on 'list_cats', 'wp_dropdown_cats' run inside this call, and their cost is not bounded by anything here.

Called by

7

7 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_terms()called directly
• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 20 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_dropdown_categories() can have, taken from its control-flow graph on PHP 8.5.

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 4

4 hooks fire while wp_dropdown_categories() runs, in this order:

1. 1
   apply_filters( list_cats )filterline 437 (+93 into the body)

   Filters a taxonomy drop-down display element.

2. 2
   apply_filters( list_cats )filterline 446 (+102 into the body)

   Filters a taxonomy drop-down display element.

3. 3
   apply_filters( list_cats )filterline 454 (+110 into the body)

   Filters a taxonomy drop-down display element.

4. 4
   apply_filters( wp_dropdown_cats )filterline 479 (+135 into the body)

   Filters the taxonomy drop-down output.

Uses · 10

• is_category()Determines whether the query is for an existing category archive page.
• get_query_var()Retrieves the value of a query variable in the WP_Query class.
• _deprecated_argument()Marks a function argument as deprecated and inform when it has been used.
• __()Retrieves the translation of $text.
• wp_parse_args()Merges user defined arguments into defaults array.
• get_terms()Retrieves the terms in a given taxonomy or list of taxonomies.
• esc_attr()Escaping for HTML attributes.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• selected()Outputs the HTML selected attribute.
• walk_category_dropdown_tree()Retrieves HTML dropdown (select) content for category list.

Used by · 7

• WP_Links_List_Table::extra_tablenav()
• WP_Posts_List_Table::categories_dropdown()Displays a categories drop-down for filtering on the Posts list table.
• WP_Widget_Categories::widget()Outputs the content for the current Categories widget instance.
• _wp_ajax_add_hierarchical_term()Handles adding a hierarchical term via AJAX.
• dropdown_cats()Deprecated method for generating a drop-down of categories.
• post_categories_meta_box()Displays post categories form fields.
• render_block_core_categories()Renders the `core/categories` block on server.

Source code

View on Trac ↗View on GitHub ↗

344function wp_dropdown_categories( $args = '' ) {345	$defaults = array(346		'show_option_all'   => '',347		'show_option_none'  => '',348		'orderby'           => 'id',349		'order'             => 'ASC',350		'show_count'        => 0,351		'hide_empty'        => 1,352		'child_of'          => 0,353		'exclude'           => '',354		'echo'              => 1,355		'selected'          => 0,356		'hierarchical'      => 0,357		'name'              => 'cat',358		'id'                => '',359		'class'             => 'postform',360		'depth'             => 0,361		'tab_index'         => 0,362		'taxonomy'          => 'category',363		'hide_if_empty'     => false,364		'option_none_value' => -1,365		'value_field'       => 'term_id',366		'required'          => false,367		'aria_describedby'  => '',368	);369 370	$defaults['selected'] = ( is_category() ) ? get_query_var( 'cat' ) : 0;371 372	// Back compat.373	if ( isset( $args['type'] ) && 'link' === $args['type'] ) {374		_deprecated_argument(375			__FUNCTION__,376			'3.0.0',377			sprintf(378				/* translators: 1: "type => link", 2: "taxonomy => link_category" */379				__( '%1$s is deprecated. Use %2$s instead.' ),380				'<code>type => link</code>',381				'<code>taxonomy => link_category</code>'382			)383		);384		$args['taxonomy'] = 'link_category';385	}386 387	// Parse incoming $args into an array and merge it with $defaults.388	$parsed_args = wp_parse_args( $args, $defaults );389 390	$option_none_value = $parsed_args['option_none_value'];391 392	if ( ! isset( $parsed_args['pad_counts'] ) && $parsed_args['show_count'] && $parsed_args['hierarchical'] ) {393		$parsed_args['pad_counts'] = true;394	}395 396	$tab_index = $parsed_args['tab_index'];397 398	$tab_index_attribute = '';399	if ( (int) $tab_index > 0 ) {400		$tab_index_attribute = " tabindex=\"$tab_index\"";401	}402 403	// Avoid clashes with the 'name' param of get_terms().404	$get_terms_args = $parsed_args;405	unset( $get_terms_args['name'] );406	$categories = get_terms( $get_terms_args );407 408	$name     = esc_attr( $parsed_args['name'] );409	$class    = esc_attr( $parsed_args['class'] );410	$id       = $parsed_args['id'] ? esc_attr( $parsed_args['id'] ) : $name;411	$required = $parsed_args['required'] ? 'required' : '';412 413	$aria_describedby_attribute = $parsed_args['aria_describedby'] ? ' aria-describedby="' . esc_attr( $parsed_args['aria_describedby'] ) . '"' : '';414 415	if ( ! $parsed_args['hide_if_empty'] || ! empty( $categories ) ) {416		$output = "<select $required name='$name' id='$id' class='$class'$tab_index_attribute$aria_describedby_attribute>\n";417	} else {418		$output = '';419	}420	if ( empty( $categories ) && ! $parsed_args['hide_if_empty'] && ! empty( $parsed_args['show_option_none'] ) ) {421 422		/**423		 * Filters a taxonomy drop-down display element.

Changelog

Introduced in 6.1.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/category-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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