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_rest_array_intersect_key_recursive( array $array1, array $array2 ): array

Since
5.3.0
Source
wp-includes/rest-api.php:917
Recursively computes the intersection of arrays using keys for comparison.

Compatibility

WordPress
since 5.3.0
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

$array1array
The array with master keys to check.
$array2array
An array to compare keys against.

Return value

array
An associative array containing all the entries of array1 which have keys that are present in all arguments.

Performance profile

How much work a call to _rest_array_intersect_key_recursive() 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
Light

Touches nothing outside its own arguments.

Scaling
Scales with input

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

Instructions
10–11

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 26.

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 one call costs · 1 distinct outcome

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

WhenInstructionsCalls it makes
always10–11array_intersect_key()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 26 instructions, 10–11 executed per call, 4 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

Used by · 2

Source code

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function _rest_array_intersect_key_recursive( $array1, $array2 ) {	$array1 = array_intersect_key( $array1, $array2 );	foreach ( $array1 as $key => $value ) {		if ( is_array( $value ) && is_array( $array2[ $key ] ) ) {			$array1[ $key ] = _rest_array_intersect_key_recursive( $value, $array2[ $key ] );		}	}	return $array1;}

Changelog

Introduced in 5.3.0. 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/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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