reduceRight()

The reduceRight() method all similar to reduce(), but It works in reverse order.

Example.php
<?php use kim\present\utils\arrays\ArrayUtils;
​
$arrayUtils = ArrayUtils::from(range(1, 10));
​
//This is like a 10 factorial
$arrayUtils->reduceRight(function($accumulator, $value){ return $accumulator * $value; }, 1);
// expected output: 3628800
​
​
​
$arrayUtils->reduceRight(
    function($accumulator, $value){
        echo  "$accumulator * $value = " . ($accumulator * $value) . PHP_EOL;
        return $accumulator * $value; }, 1));
//echo 1 * 10 = 10
//echo 10 * 9 = 90
//echo 90 * 8 = 720
//echo 720 * 7 = 5040
//echo 5040 * 6 = 30240
//echo 30240 * 5 = 151200
//echo 151200 * 4 = 604800
//echo 604800 * 3 = 1814400
//echo 1814400 * 2 = 3628800
//echo 3628800 * 1 = 3628800
//expected output: 3628800
Syntax
$arrayUtils->reduceRight(callable $callback, mixed $initialValue = null) : mixed;
Parameter
$callback
A function that produces an element of the new Array, taking four arguments:
$accumulatorThe accumulator accumulates callback's return values. It is the accumulated value previously returned in the last invocation of the callback—or $initialValue, if it was supplied (see below).
$value The current element being processed in the array.
$key The index of the current element being processed in the array.
$array   The array every was called upon.
$initialValue 
 
A value to use as the first argument to the first call of the callback.
Return value
The result value.
Prefixing
ArrayUtils::reduceRightFrom(iterable $from, callable $callback, mixed $initialValue = null) : mixed;
References
reduce()
Array.prototype.reduceRight() - JavaScript | MDN
​

reduce()

sum()

Last modified 2yr ago