get_all_category_ids() │ WP 2.0.0

Deprecated since 4.0.0. It is no longer supported and may be removed in future releases. Use get_terms() instead.

Gets the identifiers (ID) of all categories.

From version 4.0 and above, the function is deprecated, use get_terms() instead.

Returns an array containing the IDs of all categories.

Uses: get_terms()

No Hooks.

Returns

Int[].

Usage

$category_ids = get_all_category_ids();

Examples

0

#1 Display the list of category IDs and their names, in the format identifier:name 

$category_ids = get_all_category_ids();

foreach( $category_ids as $cat_id ){

	$cat_name = get_cat_name( $cat_id );

	echo "{$cat_id}: {$cat_name}<br />";
}

Notes

Changelog

Since 2.0.0 Introduced.
Deprecated since 4.0.0 Use get_terms()

get_all_category_ids() code WP 7.0

wp-includes/deprecated.php 
function get_all_category_ids() {
	_deprecated_function( __FUNCTION__, '4.0.0', 'get_terms()' );

	$cat_ids = get_terms(
		array(
			'taxonomy' => 'category',
			'fields'   => 'ids',
			'get'      => 'all',
		)
	);

	return $cat_ids;
}