PHP | Ds\Map reduce() Function Last Updated : 21 Aug, 2019 Comments Improve Suggest changes Like Article Like Report The Ds\Map::reduce() function is an inbuilt function in PHP which is used to reduce the map to a single value by applying operations using the callback function. Syntax: mixed public Ds\Map::reduce( $callback, $initial ) Parameter: This function accepts two parameters as mentioned above and described below: $callback: This parameter holds the function which contains the operation on the elements and store carry. This callback function contains three arguments which are listed below: carry: It holds the return value of the previous callback, or initial if it's the first iteration. key: It holds the key of the current iteration. value: It holds the value of the current iteration. $initial: This parameter holds the initial value of carry, which can be NULL. Return value: This function returns the final value returned by the callback function. Below programs illustrate the Ds\Map::reduce() function in PHP: Program 1: php <?php // Declare a new map $map = new \Ds\Map(["a" => 1, "b" => 3, "c" => 5]); echo("Map Elements\n"); print_r($map); // Callback function with reduce function echo("\nElement after performing operation\n"); var_dump($map->reduce(function($carry, $key, $element) { return $carry + $element + 2; })); ?> Output: Map Elements Ds\Map Object ( [0] => Ds\Pair Object ( [key] => a [value] => 1 ) [1] => Ds\Pair Object ( [key] => b [value] => 3 ) [2] => Ds\Pair Object ( [key] => c [value] => 5 ) ) Element after performing operation int(15) Program 2: php <?php // Declare new Map elements $map = new \Ds\Map(["a" => 10, "b" => 20, "c" => 30, "d" => 40, "e" => 50]); echo("Original map elements\n"); print_r($map); $func_gfg = function($carry, $key, $element) { return $carry * $element; }; echo("\nMap after reducing to single element\n"); // Use reduce() function var_dump($map->reduce($func_gfg, 10)); ?> Output: Original map elements Ds\Map Object ( [0] => Ds\Pair Object ( [key] => a [value] => 10 ) [1] => Ds\Pair Object ( [key] => b [value] => 20 ) [2] => Ds\Pair Object ( [key] => c [value] => 30 ) [3] => Ds\Pair Object ( [key] => d [value] => 40 ) [4] => Ds\Pair Object ( [key] => e [value] => 50 ) ) Map after reducing to single element int(120000000) Reference: https://www.php.net/manual/en/ds-map.reduce.php Comment More infoAdvertise with us Next Article PHP | Ds\Map reduce() Function R R_Raj Follow Improve Article Tags : Web Technologies PHP PHP-function PHP-ds_map Similar Reads PHP | DsSet reduce() Function The Ds\Set::reduce() function is an inbuilt function in PHP which is used to reduce the set to a single value by applying operations using the callback function. Syntax: mixed public Ds\Set::reduce ( callable $callback [, mixed $initial ] ) Parameters: This function accepts two parameters as mention 2 min read PHP | DsVector reduce() Function The Ds\Vector::reduce() function is an inbuilt function in PHP which reduce the vector to a single value by applying operations in the callback function. Syntax: mixed public Ds\Vector::reduce( $callback, $initial ) Parameters: This function accepts two parameters as mentioned above and described be 2 min read PHP | DsSequence reduce() Function The Ds\Sequence::reduce() function is an inbuilt function in PHP which is used to reduce the sequence to a single value using a callback function. Syntax: mixed abstract public Ds\Sequence::reduce ( callable $callback [, mixed $initial ] ) Parameters: This function accepts two parameters as mentione 2 min read PHP array_reduce() Function This inbuilt function of PHP is used to reduce the elements of an array into a single value that can be of float, integer or string value. The function uses a user-defined callback function to reduce the input array. Syntax: array_reduce($array, own_function, $initial) Parameters: The function takes 2 min read PHP | DsDeque map() Function The Ds\Deque::map() function is an inbuilt function in PHP which is used to return the Deque with each element modified on the basis of operation performed as per the callback function. Syntax: public Ds\Deque::map( $callback ) : Ds\Deque Parameters: This function accepts single parameter $callback 2 min read Like