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get_category( int|object $category, string $output = OBJECT, string $filter = 'raw' ): WP_Term|array|WP_Error|null

Since
1.5.1
Source
wp-includes/category.php:92
Retrieves category data given a category ID or category object.

Description

If you pass the $category parameter an object, which is assumed to be the category row object retrieved the database. It will cache the category data.

If you pass $category an integer of the category ID, then that category will be retrieved from the database, if it isn't already cached, and pass it back.

If you look at get_term(), then both types will be passed through several filters and finally sanitized based on the $filter parameter value.

Compatibility

WordPress
since 1.5.1
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

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

Parameters

$categoryint|object
Category ID or category row object.
$outputstringoptional
The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which correspond to a WP_Term object, an associative array, or a numeric array, respectively. Default OBJECT.Default: OBJECT
$filterstringoptional
How to sanitize category fields. Default 'raw'.Default: 'raw'

Return value

WP_Term|array|WP_Error|null
Category data in type defined by $output parameter.
Returns a WP_Term object with backwards compatible property aliases filled in.
WP_Error if $category is empty, null if it does not exist.

Performance profile

How much work a call to get_category() 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_term().

Scaling
Constant

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

Instructions
15–18

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 19.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
2

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

What it touches

  • querycontent queryget_term()called directly
  • hookthird-party callbacksapply_filters()one call below get_category()

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 · 2 distinct outcomes

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

WhenInstructionsCalls it makes
is_wp_error()15get_term(), is_wp_error()
!is_wp_error()18get_term(), is_wp_error(), _make_cat_compat()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 19 instructions, 15–18 executed per call, 1 branch. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 3

  • get_term()Gets all term data from database by term ID.
  • is_wp_error()Checks whether the given variable is a WordPress Error.
  • _make_cat_compat()Updates category structure to old pre-2.3 from new taxonomy structure.

Used by · 2

Source code

View on Trac View on GitHub 

function get_category( $category, $output = OBJECT, $filter = 'raw' ) {	$category = get_term( $category, 'category', $output, $filter ); 	if ( is_wp_error( $category ) ) {		return $category;	} 	_make_cat_compat( $category ); 	return $category;}

Changelog

Introduced in 1.5.1. One change between 6.7.7 and 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.

6.8.8
Return type changed from object|array|WP_Error|null to WP_Term|array|WP_Error|null.verified against source
1.5.1
Introduced.from the docblock

About this page

Parsed data
Generated from the wordpress-develop 6.8.8 tag, from src/wp-includes/category.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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