Ds\Deque::reduce
(PECL ds >= 1.0.0)
Ds\Deque::reduce — Reduces the deque to a single value using a callback function
Description
public Ds\Deque::reduce ( callable $callback [, mixed $initial ] ) : mixed
Reduces the deque to a single value using a callback function.
Parameters
-
callback
-
callback ( mixed $carry , mixed $value ) : mixed
-
carry
-
The return value of the previous callback, or
initial
if it's the first iteration. -
value
-
The value of the current iteration.
-
-
initial
-
The initial value of the carry value. Can be
null
.
Return Values
The return value of the final callback.
Examples
Example #1 Ds\Deque::reduce() with initial value example
<?php $deque = new \Ds\Deque([1, 2, 3]); $callback = function($carry, $value) { return $carry * $value; }; var_dump($deque->reduce($callback, 5)); // Iterations: // // $carry = $initial = 5 // // $carry = $carry * 1 = 5 // $carry = $carry * 2 = 10 // $carry = $carry * 3 = 30 ?>
The above example will output something similar to:
int(30)
Example #2 Ds\Deque::reduce() without an initial value example
<?php $deque = new \Ds\Deque([1, 2, 3]); var_dump($deque->reduce(function($carry, $value) { return $carry + $value + 5; })); // Iterations: // // $carry = $initial = null // // $carry = $carry + 1 + 5 = 6 // $carry = $carry + 2 + 5 = 13 // $carry = $carry + 3 + 5 = 21 ?>
The above example will output something similar to:
int(21)
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https://www.php.net/manual/en/ds-deque.reduce.php