Using WordPress ‘map_deep()’ PHP function

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The map_deep() WordPress PHP function maps a function to all non-iterable elements of an array or an object. This is similar to array_walk_recursive() but acts upon objects too.

Usage

map_deep( $value, $callback );

Parameters

  • $value (mixed) – The array, object, or scalar to be processed.
  • $callback (callable) – The function to map onto $value.

More information

See WordPress Developer Resources: map_deep
Introduced in WordPress version 4.4.0.

Examples

Sanitizing a simple array

Sanitizing an array with user input using sanitize_text_field function:

$values = array( 'a', '<b>Test</b>', '<>c' );
$values = map_deep( $values, 'sanitize_text_field' );
// Output: array( 'a', 'Test', 'c' )

Sanitizing a multidimensional array

Sanitizing a multidimensional array with user input using sanitize_text_field function:

$values = array( 'option_1' => 'value of this option', 'option_2' => '<b>value of this option</b>' );
$values = map_deep( $values, 'sanitize_text_field' );
// Output: array( 'option_1' => 'value of this option', 'option_2' => 'value of this option' )

Escaping a simple array for output

Escaping an array with user input using esc_html function:

$values = array( 'a', '<b>Test</b>', '<>c' );
$values = map_deep( $values, 'esc_html' );
// Output: array( 'a', '&lt;b&gt;Test&lt;/b&gt;', '&lt;&gt;c' )

Processing a nested array with custom callback

Using a custom callback to process a nested array:

$values = array( 'a', 'b', array( 'c', 'd', 'e' ) );
$values = map_deep( $values, function( $item ) {
    return strtoupper( $item );
});
// Output: array( 'A', 'B', array( 'C', 'D', 'E' ) )

Processing an object with a custom callback

Using a custom callback to process an object:

class Example {
    public $property1 = 'text1';
    public $property2 = 'text2';
}

$object = new Example();
$object = map_deep( $object, function( $item ) {
    return strtoupper( $item );
});
// Output: object( 'property1' => 'TEXT1', 'property2' => 'TEXT2' )