(PECL ds >= 1.0.0)
Ds\Set::reduce — Reduces the set to a single value using a callback function
Reduces the set to a single value using a callback function.
callback
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
.
The return value of the final callback.
Example #1 Ds\Set::reduce() with initial value example
<?php
$set = new \Ds\Set([1, 2, 3]);
$callback = function($carry, $value) {
return $carry * $value;
};
var_dump($set->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\Set::reduce() without an initial value example
<?php
$set = new \Ds\Set([1, 2, 3]);
var_dump($set->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)