Ds\Sequence::reduce

(PECL ds >= 1.0.0)

Ds\Sequence::reduceReduces the sequence to a single value using a callback function

Descrição

abstract public Ds\Sequence::reduce(callable $callback, mixed $initial = ?): mixed

Reduces the sequence to a single value using a callback function.

Parâmetros

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.

Valor Retornado

The return value of the final callback.

Exemplos

Exemplo #1 Ds\Sequence::reduce() with initial value example

<?php
$sequence
= new \Ds\Vector([1, 2, 3]);

$callback = function($carry, $value) {
return
$carry * $value;
};

var_dump($sequence->reduce($callback, 5));

// Iterations:
//
// $carry = $initial = 5
//
// $carry = $carry * 1 = 5
// $carry = $carry * 2 = 10
// $carry = $carry * 3 = 30
?>

O exemplo acima produzirá algo semelhante a:

int(30)

Exemplo #2 Ds\Sequence::reduce() without an initial value example

<?php
$sequence
= new \Ds\Vector([1, 2, 3]);

var_dump($sequence->reduce(function($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
?>

O exemplo acima produzirá algo semelhante a:

int(21)
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