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WP_List_Util::filter( array $args = array(), string $operator = 'AND' ): array

Since
4.7.0
Source
wp-includes/class-wp-list-util.php:98
Filters the list, based on a set of key => value arguments.

Description

Retrieves the objects from the list that match the given arguments.
Key represents property name, and value represents property value.

If an object has more properties than those specified in arguments, that will not disqualify it. When using the 'AND' operator, any missing properties will disqualify it.

Compatibility

WordPress
since 4.7.0
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

$argsarrayoptional
An array of key => value arguments to match against each object. Default empty array.Default: array()
$operatorstringoptional
The logical operation to perform. 'AND' means all elements from the array must match. 'OR' means only one element needs to match. 'NOT' means no elements may match. Default 'AND'.Default: 'AND'

Return value

array
Array of found values.

Performance profile

How much work a call to WP_List_Util::filter() 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
6–20

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 65.

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 · 2 distinct outcomes

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

WhenInstructionsCalls it makes
empty($args)6none
!empty($args)14–20strtoupper()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 65 instructions, 6–20 executed per call, 18 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.

Source code

	public function filter( $args = array(), $operator = 'AND' ) {		if ( empty( $args ) ) {			return $this->output;		} 		$operator = strtoupper( $operator ); 		if ( ! in_array( $operator, array( 'AND', 'OR', 'NOT' ), true ) ) {			$this->output = array();			return $this->output;		} 		$count    = count( $args );		$filtered = array(); 		foreach ( $this->output as $key => $obj ) {			$matched = 0; 			foreach ( $args as $m_key => $m_value ) {				if ( is_array( $obj ) ) {					// Treat object as an array.					if ( array_key_exists( $m_key, $obj ) && ( $m_value == $obj[ $m_key ] ) ) {						++$matched;					}				} elseif ( is_object( $obj ) ) {					// Treat object as an object.					if ( isset( $obj->{$m_key} ) && ( $m_value == $obj->{$m_key} ) ) {						++$matched;					}				}			} 			if ( ( 'AND' === $operator && $matched === $count )				|| ( 'OR' === $operator && $matched > 0 )				|| ( 'NOT' === $operator && 0 === $matched )			) {				$filtered[ $key ] = $obj;			}		} 		$this->output = $filtered; 		return $this->output;	}

Changelog

Introduced in 4.7.0. 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 7.1.0 tag, from src/wp-includes/class-wp-list-util.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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