array_replace_recursive

Array Functions

array_reduce

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

Description

mixed array_reduce ( array $array , callable $callback [, mixed $initial = NULL ] )

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

Parameters

array: The input array.
callback: The callback function.

mixed callback ( mixed &$result , mixed $item )
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.

Changelog

Version	Description
5.3.0	Changed `initial` to allow mixed, previously integer.

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", "No data to reduce");
?>

This will result in $b containing 15, $c containing 1200 (= 10*1*2*3*4*5), and $d containing No data to reduce.

See Also

array_filter
array_map
array_unique
array_count_values