wppaste
WordPress

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

Since
2.3.0
Source
wp-includes/category.php:341
Retrieves a post tag by tag ID or tag object.

Description

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

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

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

Compatibility

WordPress
since 2.3.0
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

$tagint|WP_Term|object
A tag ID or 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 tag fields. Default 'raw'.Default: 'raw'

Return value

WP_Term|array|WP_Error|null
Tag data in type defined by $output parameter.
WP_Error if $tag is empty, null if it does not exist.

Performance profile

How much work a call to get_tag() 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
10

Executed per call on PHP 8.5. The body compiles to 10.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

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

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 · 1 distinct outcome

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

WhenInstructionsCalls it makes
always10get_term()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 10 instructions, 10 executed per call, 0 branches. 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 · 1

  • get_term()Gets all term data from database by term ID.

Source code

View on Trac View on GitHub 

function get_tag( $tag, $output = OBJECT, $filter = 'raw' ) {	return get_term( $tag, 'post_tag', $output, $filter );}

Changelog

Introduced in 2.3.0. 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 6.9.7 tag, from src/wp-includes/category.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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