Ds\Vector::reduce
Ds\Vector::reduce
(PECL ds >= 1.0.0)
Ds\Vector::reduce — Reduces the vector to a single value using a callback function.
Description
public mixed Ds\Vector::reduce ( callable $callback [, mixed $initial ] )
Reduces the vector to a single value using a callback function.
Parameters
-
callback -
mixed callback ( mixed $carry , mixed $value )
-
carry -
The return value of the previous callback, or
initialif 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\Vector::reduce() with initial value example
<?php
$vector = new \Ds\Vector([1, 2, 3]);
$callback = function($carry, $value) {
return $carry * $value;
};
var_dump($vector->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\Vector::reduce() without an initial value example
<?php
$vector = new \Ds\Vector([1, 2, 3]);
var_dump($vector->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://secure.php.net/manual/en/ds-vector.reduce.php
