Php/docs/function.array-reduce
array_reduce
(PHP 4 >= 4.0.5, PHP 5, PHP 7)
array_reduce — Iteratively reduce the array to a single value using a callback function
Description
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
-
carry
Holds the return value of the previous iteration; in the case of the first iteration it instead holds the value of
initial
.item
Holds the value of the current iteration.
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
<?phpfunction sum($carry, $item){ $carry += $item; return $carry;}function product($carry, $item){ $carry *= $item; return $carry;}$a = array(1, 2, 3, 4, 5);$x = array();var_dump(array_reduce($a, "sum")); // int(15)var_dump(array_reduce($a, "product", 10)); // int(1200), because: 10*1*2*3*4*5var_dump(array_reduce($x, "sum", "No data to reduce")); // string(17) "No data to reduce"?>
See Also
- array_filter() - Filters elements of an array using a callback function
- array_map() - Applies the callback to the elements of the given arrays
- array_unique() - Removes duplicate values from an array
- array_count_values() - Counts all the values of an array