The Ds\Deque::reduce() function is an inbuilt function in PHP which is used to reduce the Deque to a single element using callback function.
Syntax:
public Ds\Deque::reduce( $callback, $initial ) : mixed
Parameters: This function accept two parameters as mentioned above and described below:
- callable: It contains the operation to be performed on the elements of Deque resulting into a single element.
- value: It holds the initial value of carry which will be the result after performing operation on all elements.
Return Value: This function returns the final value returned by the callback function.
Below programs illustrate the Ds\Deque::reduce() function in PHP:
Program 1:
<?php // Declare a deque $deck = new \Ds\Deque([10, 20, 30, 40, 50, 60]);
echo ( "Elements of Deque\n" );
// Display the Deque elements print_r( $deck );
// Function to perform operation on deque $func = function ( $carry , $element ) {
return $carry + $element ;
}; echo ( "\nDeque after reduced into single element: " );
// use reduce() function var_dump( $deck ->reduce( $func , 5));
?> |
Output:
Elements of Deque Ds\Deque Object ( [0] => 10 [1] => 20 [2] => 30 [3] => 40 [4] => 50 [5] => 60 ) Deque after reduced into single element: int(215)
Program 2:
<?php // Declare a deque $deck = new \Ds\Deque([10, 20, 30, 40, 50, 60]);
echo ( "Elements of Deque\n" );
// Display the Deque elements print_r( $deck );
// Function to perform operation on deque $func = function ( $carry , $element ) {
return $carry * $element + 20;
}; echo ( "\nDeque after reduced into single element: " );
// use reduce() function var_dump( $deck ->reduce( $func , 10));
?> |
Output:
Elements of Deque Ds\Deque Object ( [0] => 10 [1] => 20 [2] => 30 [3] => 40 [4] => 50 [5] => 60 ) Deque after reduced into single element: int(8714461220)
Reference: http://php.net/manual/en/ds-deque.reduce.php