* A class of utilities for dealing with arrays.
declare( strict_types = 1 );
namespace Automattic\WooCommerce\Utilities;
* A class of utilities for dealing with arrays.
* Automatic selector type for the 'select' method.
public const SELECT_BY_AUTO = 0;
* Object method selector type for the 'select' method.
public const SELECT_BY_OBJECT_METHOD = 1;
* Object property selector type for the 'select' method.
public const SELECT_BY_OBJECT_PROPERTY = 2;
* Array key selector type for the 'select' method.
public const SELECT_BY_ARRAY_KEY = 3;
* Get a value from an nested array by specifying the entire key hierarchy with '::' as separator.
* E.g. for [ 'foo' => [ 'bar' => [ 'fizz' => 'buzz' ] ] ] the value for key 'foo::bar::fizz' would be 'buzz'.
* @param array $items The array to get the value from.
* @param string $key The complete key hierarchy, using '::' as separator.
* @param mixed $default_value The value to return if the key doesn't exist in the array.
* @return mixed The retrieved value, or the supplied default value.
* @throws \Exception $array is not an array.
public static function get_nested_value( array $items, string $key, $default_value = null ) {
$key_stack = explode( '::', $key );
$subkey = array_shift( $key_stack );
if ( isset( $items[ $subkey ] ) ) {
$value = $items[ $subkey ];
if ( count( $key_stack ) ) {
foreach ( $key_stack as $subkey ) {
if ( is_array( $value ) && isset( $value[ $subkey ] ) ) {
$value = $value[ $subkey ];
* Checks if a given key exists in an array and its value can be evaluated as 'true'.
* @param array $items The array to check.
* @param string $key The key for the value to check.
* @return bool True if the key exists in the array and the value can be evaluated as 'true'.
public static function is_truthy( array $items, string $key ) {
return isset( $items[ $key ] ) && $items[ $key ];
* Gets the value for a given key from an array, or a default value if the key doesn't exist in the array.
* This is equivalent to "$array[$key] ?? $default" except in one case:
* when they key exists, has a null value, and a non-null default is supplied:
* $array = ['key' => null]
* $array['key'] ?? 'default' => 'default'
* ArrayUtil::get_value_or_default($array, 'key', 'default') => null
* @param array $items The array to get the value from.
* @param string $key The key to use to retrieve the value.
* @param null $default_value The default value to return if the key doesn't exist in the array.
* @return mixed|null The value for the key, or the default value passed.
public static function get_value_or_default( array $items, string $key, $default_value = null ) {
return array_key_exists( $key, $items ) ? $items[ $key ] : $default_value;
* Converts an array of numbers to a human-readable range, such as "1,2,3,5" to "1-3, 5". It also supports
* floating point numbers, however with some perhaps unexpected / undefined behaviour if used within a range.
* Source: https://stackoverflow.com/a/34254663/4574
* @param array $items An array (in any order, see $sort) of individual numbers.
* @param string $item_separator The string that separates sequential range groups. Defaults to ', '.
* @param string $range_separator The string that separates ranges. Defaults to '-'. A plausible example otherwise would be ' to '.
* @param bool|true $sort Sort the array prior to iterating? You'll likely always want to sort, but if not, you can set this to false.
public static function to_ranges_string( array $items, string $item_separator = ', ', string $range_separator = '-', bool $sort = true ): string {
foreach ( $items as $i ) {
} elseif ( ( $point + 1 ) === $i ) {
$str .= $range_separator . $point;
$str .= $item_separator . $i;
$str .= $range_separator . $point;
* Helper function to generate a callback which can be executed on an array to select a value from each item.
* @param string $selector_name Field/property/method name to select.
* @param int $selector_type Selector type.
* @return \Closure Callback to select the value.
private static function get_selector_callback( string $selector_name, int $selector_type = self::SELECT_BY_AUTO ): \Closure {
if ( self::SELECT_BY_OBJECT_METHOD === $selector_type ) {
$callback = function ( $item ) use ( $selector_name ) {
return $item->$selector_name();
} elseif ( self::SELECT_BY_OBJECT_PROPERTY === $selector_type ) {
$callback = function ( $item ) use ( $selector_name ) {
return $item->$selector_name;
} elseif ( self::SELECT_BY_ARRAY_KEY === $selector_type ) {
$callback = function ( $item ) use ( $selector_name ) {
return $item[ $selector_name ];
$callback = function ( $item ) use ( $selector_name ) {
if ( is_array( $item ) ) {
return $item[ $selector_name ];
} elseif ( method_exists( $item, $selector_name ) ) {
return $item->$selector_name();
return $item->$selector_name;
* Select one single value from all the items in an array of either arrays or objects based on a selector.
* For arrays, the selector is a key name; for objects, the selector can be either a method name or a property name.
* @param array $items Items to apply the selection to.
* @param string $selector_name Key, method or property name to use as a selector.
* @param int $selector_type Selector type, one of the SELECT_BY_* constants.
* @return array The selected values.
public static function select( array $items, string $selector_name, int $selector_type = self::SELECT_BY_AUTO ): array {
$callback = self::get_selector_callback( $selector_name, $selector_type );
return array_map( $callback, $items );
* Returns a new assoc array with format [ $key1 => $item1, $key2 => $item2, ... ] where $key is the value of the selector and items are original items passed.
* @param array $items Items to use for conversion.
* @param string $selector_name Key, method or property name to use as a selector.
* @param int $selector_type Selector type, one of the SELECT_BY_* constants.
* @return array The converted assoc array.
public static function select_as_assoc( array $items, string $selector_name, int $selector_type = self::SELECT_BY_AUTO ): array {
$selector_callback = self::get_selector_callback( $selector_name, $selector_type );
foreach ( $items as $item ) {
$key = $selector_callback( $item );
self::ensure_key_is_array( $result, $key );
$result[ $key ][] = $item;
* Returns whether two assoc array are same. The comparison is done recursively by keys, and the functions returns on first difference found.
* @param array $array1 First array to compare.
* @param array $array2 Second array to compare.
* @param bool $strict Whether to use strict comparison.
* @return bool Whether the arrays are different.
public static function deep_compare_array_diff( array $array1, array $array2, bool $strict = true ) {
return self::deep_compute_or_compare_array_diff( $array1, $array2, true, $strict );
* Computes difference between two assoc arrays recursively. Similar to PHP's native assoc_array_diff, but also supports nested arrays.
* @param array $array1 First array.
* @param array $array2 Second array.
* @param bool $strict Whether to also match type of values.
* @return array The difference between the two arrays.
public static function deep_assoc_array_diff( array $array1, array $array2, bool $strict = true ): array {
return self::deep_compute_or_compare_array_diff( $array1, $array2, false, $strict );
* Helper method to compare to compute difference between two arrays. Comparison is done recursively.
* @param array $array1 First array.
* @param array $array2 Second array.
* @param bool $compare Whether to compare the arrays. If true, then function will return false on first difference, in order to be slightly more efficient.
* @param bool $strict Whether to do string comparison.
* @return array|bool The difference between the two arrays, or if array are same, depending upon $compare param.
private static function deep_compute_or_compare_array_diff( array $array1, array $array2, bool $compare, bool $strict = true ) {
foreach ( $array1 as $key => $value ) {
if ( is_array( $value ) ) {
if ( ! array_key_exists( $key, $array2 ) || ! is_array( $array2[ $key ] ) ) {
$new_diff = self::deep_assoc_array_diff( $value, $array2[ $key ], $strict );
if ( ! empty( $new_diff ) ) {
$diff[ $key ] = $new_diff;
if ( ! array_key_exists( $key, $array2 ) || $value !== $array2[ $key ] ) {
// phpcs:ignore Universal.Operators.StrictComparisons.LooseNotEqual -- Intentional when $strict is false.
} elseif ( ! array_key_exists( $key, $array2 ) || $value != $array2[ $key ] ) {
return $compare ? false : $diff;
* Push a value to an array, but only if the value isn't in the array already.
* @param array $items The array.
* @param mixed $value The value to maybe push.
* @return bool True if the value has been added to the array, false if the value was already in the array.
public static function push_once( array &$items, $value ): bool {
if ( in_array( $value, $items, true ) ) {
* Ensure that an associative array has a given key, and if not, set the key to an empty array.
* @param array $items The array to check.
* @param string $key The key to check.
* @param bool $throw_if_existing_is_not_array If true, an exception will be thrown if the key already exists in the array but the value is not an array.
* @return bool True if the key has been added to the array, false if not (the key already existed).
* @throws \Exception The key already exists in the array but the value is not an array.
public static function ensure_key_is_array( array &$items, string $key, bool $throw_if_existing_is_not_array = false ): bool {
if ( ! isset( $items[ $key ] ) ) {
$items[ $key ] = array();
if ( $throw_if_existing_is_not_array && ! is_array( $items[ $key ] ) ) {
$type = is_object( $items[ $key ] ) ? get_class( $items[ $key ] ) : gettype( $items[ $key ] );
// phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
throw new \Exception( "Array key exists but it's not an array, it's a {$type}" );
* Given an array of associative arrays, all having a shared key name ("column"), generates a new array in which
* keys are the distinct column values found, and values are arrays with all the matches found
* (or only the last matching array found, if $single_values is true).
* See ArrayUtilTest for examples.
* @param array $items The array to process.
* @param string $column The name of the key to group by.
* @param bool $single_values True to only return the last suitable array found for each column value.
* @return array The grouped array.
public static function group_by_column( array $items, string $column, bool $single_values = false ): array {
return array_combine( array_column( $items, $column ), array_values( $items ) );
$distinct_column_values = array_unique( array_column( $items, $column ), SORT_REGULAR );
$result = array_fill_keys( $distinct_column_values, array() );
foreach ( $items as $value ) {
$result[ $value[ $column ] ][] = $value;
* Check if all items in an array pass a callback.
* @param array $items The array to check.
* @param callable $callback The callback to check each item.
* @return bool true if all items pass the callback, false otherwise.
public static function array_all( array $items, callable $callback ): bool {
if ( function_exists( 'array_all' ) ) {
return array_all( $items, $callback );
foreach ( $items as $item ) {
if ( ! $callback( $item ) ) {
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
