Description
array
array_map ( callback callback, array arr1 [, array ...] )
array_map() returns an array containing all
the elements of arr1
after applying the
callback
function to each one.
The number of parameters that the callback
function accepts
should match the number of arrays
passed to the array_map()
PÅ™Ãklad 1. array_map() example
<?php function cube($n) { return($n * $n * $n); }
$a = array(1, 2, 3, 4, 5); $b = array_map("cube", $a); print_r($b); ?>
|
This makes $b have:
Array
(
[0] => 1
[1] => 8
[2] => 27
[3] => 64
[4] => 125
) |
|
PÅ™Ãklad 2. array_map() - using more arrays
<?php function show_Spanish($n, $m) { return("The number $n is called $m in Spanish"); }
function map_Spanish($n, $m) { return(array($n => $m)); }
$a = array(1, 2, 3, 4, 5); $b = array("uno", "dos", "tres", "cuatro", "cinco");
$c = array_map("show_Spanish", $a, $b); print_r($c);
$d = array_map("map_Spanish", $a , $b); print_r($d); ?>
|
Výše uvedený pÅ™Ãklad vypÃÅ¡e: // printout of $c
Array
(
[0] => The number 1 is called uno in Spanish
[1] => The number 2 is called dos in Spanish
[2] => The number 3 is called tres in Spanish
[3] => The number 4 is called cuatro in Spanish
[4] => The number 5 is called cinco in Spanish
)
// printout of $d
Array
(
[0] => Array
(
[1] => uno
)
[1] => Array
(
[2] => dos
)
[2] => Array
(
[3] => tres
)
[3] => Array
(
[4] => cuatro
)
[4] => Array
(
[5] => cinco
)
) |
|
Usually when using two or more arrays, they should be of equal length
because the callback function is applied in parallel to the corresponding
elements.
If the arrays are of unequal length, the shortest one will be extended
with empty elements.
An interesting use of this function is to construct an array of arrays,
which can be easily performed by using NULL
as the name of the callback function
PÅ™Ãklad 3. Creating an array of arrays
<?php $a = array(1, 2, 3, 4, 5); $b = array("one", "two", "three", "four", "five"); $c = array("uno", "dos", "tres", "cuatro", "cinco");
$d = array_map(null, $a, $b, $c); print_r($d); ?>
|
Výše uvedený pÅ™Ãklad vypÃÅ¡e: Array
(
[0] => Array
(
[0] => 1
[1] => one
[2] => uno
)
[1] => Array
(
[0] => 2
[1] => two
[2] => dos
)
[2] => Array
(
[0] => 3
[1] => three
[2] => tres
)
[3] => Array
(
[0] => 4
[1] => four
[2] => cuatro
)
[4] => Array
(
[0] => 5
[1] => five
[2] => cinco
)
) |
|
See also array_filter(),
array_reduce(),
array_walk(),
create_function(), and
informace typu callback.