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array_reduce

(PHP 4 >= 4.0.5, PHP 5)

array_reduceIteratively 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(12345);
$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

PHP Manual