PHP: Iteratively reduce the array to a single value using a callback function

Description

mixed array_reduce ( array $input , callback $function [, int $initial ] )

array_reduce() applies iteratively the function function to the elements of the array input , so as to reduce the array to a single value.

Parameters

input: The input array.
function: The callback function.
initial: If the optional initial is available, it will be used at the beginning of the process, or as a final result in case the array is empty.

Return Values

Returns the resulting value.

If the array is empty and initial is not passed, array_reduce() returns NULL.

Examples

Example #1 array_reduce() example


<?php

function rsum($v, $w)

{

    $v += $w;

    return $v;

}



function rmul($v, $w)

{

    $v *= $w;

    return $v;

}



$a = array(1, 2, 3, 4, 5);

$x = array();

$b = array_reduce($a, "rsum");

$c = array_reduce($a, "rmul", 10);

$d = array_reduce($x, "rsum", 1);

?>

This will result in $b containing 15, $c containing 1200 (= 10*1*2*3*4*5), and $d containing 1.

array_reduce

Description

Parameters

Return Values

Examples

See Also