PHP sends the values in the array to the user-defined function and returns a string of functions array_reduce ()

Instance

Sends a value from the array to the user-defined function and returns a string:

<?phpfunction MyFunction ($v 1, $v 2) {return $v 1. "-" . $v 2;} $a =array ("Dog", "Cat", "Horse");p Rint_r (array_reduce ($a, "myfunction")); >

Definition and usage

The Array_reduce () function sends a value from the array to the user-defined function and returns a string.

Note: If the array is empty or the initial value is not passed, the function returns NULL.

Grammar

Array_reduce (array,myfunction,initial)

Parameters	Describe
Array	Necessary. Specifies the array.
MyFunction	Necessary. Specifies the name of the function.
Initial	Optional. Specifies the first value to be sent to the function processing.

technical details

return value:	Returns the result value.
php version:	4.0.5+
update log:

More examples

Example 1

With initial parameters:

<?phpfunction MyFunction ($v 1, $v 2) {return $v 1. "-" . $v 2;} $a =array ("Dog", "Cat", "Horse");p Rint_r (array_reduce ($a, "MyFunction", 5)); >

Example 2

return sum:

<?phpfunction MyFunction ($v 1, $v 2) {return $v 1+ $v 2;} $a =array (10,15,20);p Rint_r (array_reduce ($a, "MyFunction", 5));? >

Array_reduce is not only so powerful. Look at the following example. POPs the first element of the array $arr as the initial value, avoiding the $result being empty in min ($result [' min '], $item [' min ']).

Otherwise the final result min is empty.

$arr = Array ('     min ' = = 1.5456, ' max ' = 2.28548, ' volume ' = 23.152),     array (' min ' = = 1.5457, ' ma X ' = 2.28549, ' volume ' + 23.152),     array (' min ' = = 1.5458, ' max ' = 2.28550, ' volume ' = 23.152),     a Rray (' min ' = 1.5459, ' max ' = 2.28551, ' volume ' + 23.152),     array (' min ' = 1.5460, ' max ' = 2.28552, ' Volume ' = 23.152),); $initial = Array_shift ($arr); $t = array_reduce ($arr, function ($result, $item) {     $result [' min '] = min ($result [' min '], $item [' min ']);     $result [' max '] = max ($result [' Max '], $item [' Max ']);     $result [' volume '] + = $item [' volume '];     return $result; }, $initial);

In short, this is more elegant than foreach and defines variables less. Recommended use.