(PHP 4 >= 4.0.5, PHP 5)
array_reduce — Iteratively reduce the array to a single value using a callback function
array_reduce() applies iteratively the
function function to the elements of the
array input, so as to reduce the array to
a single value.
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.
Returns the resulting value.
If the array is empty and initial is not passed,
array_reduce() returns NULL.
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.