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WordPress

WP_HTML_Open_Elements::at( int $nth ): WP_HTML_Token|null

Since
6.7.0
Source
wp-includes/html-api/class-wp-html-open-elements.php:119
Returns the name of the node at the nth position on the stack of open elements, or null if no such position exists.

Description

Note that this uses a 1-based index, which represents the "nth item" on the stack, counting from the top, where the top-most element is the 1st, the second is the 2nd, etc...

Compatibility

WordPress
since 6.7.0
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

$nthint
Retrieve the nth item on the stack, with 1 being the top element, 2 being the second, etc...

Return value

WP_HTML_Token|null
Name of the node on the stack at the given location, or null if the location isn't on the stack.

Performance profile

How much work a call to WP_HTML_Open_Elements::at() 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
Trivial

Touches nothing outside its own arguments.

Scaling
Scales with input

The body loops, so the work grows with what you pass in.

Instructions
6–11

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 13.

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 one call costs · 1 distinct outcome

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

WhenInstructionsCalls it makes
always6–11->walk_down()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 13 instructions, 6–11 executed per call, 3 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

Source code

View on Trac View on GitHub 

	public function at( int $nth ): ?WP_HTML_Token {		foreach ( $this->walk_down() as $item ) {			if ( 0 === --$nth ) {				return $item;			}		} 		return null;	}

Changelog

Introduced in 6.7.0. 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/html-api/class-wp-html-open-elements.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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