array_map
Applies the callback to the elements of the given arrays
&reftitle.description;
arrayarray_map
callbackcallback
arrayarr1
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
&reftitle.parameters;
callback
Callback function to run for each element in each array.
arr1
An array to run through the callback function.
array
Variable list of array arguments to run through the
callback function.
&reftitle.returnvalues;
Returns an array containing all the elements of arr1
after applying the callback function to each one.
&reftitle.examples;
<function>array_map</function> example
]]>
This makes $b have:
1
[1] => 8
[2] => 27
[3] => 64
[4] => 125
)
]]>
<function>array_map</function> using a lambda function (as of PHP 5.3.0)
]]>
2
[1] => 4
[2] => 6
[3] => 8
[4] => 10
)
]]>
&reftitle.examples;
<function>array_map</function> - using more arrays
$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);
?>
]]>
&example.outputs;
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 $d
Array
(
[0] => Array
(
[1] => uno
)
[1] => Array
(
[2] => dos
)
[2] => Array
(
[3] => tres
)
[3] => Array
(
[4] => cuatro
)
[4] => Array
(
[5] => cinco
)
)
]]>
Usually when using two or more arrays, they should be of equal length
because the callback function is applied in parallel to the corresponding
elements.
If the arrays are of unequal length, the shortest one will be extended
with empty elements.
An interesting use of this function is to construct an array of arrays,
which can be easily performed by using &null;
as the name of the callback function
Creating an array of arrays
]]>
&example.outputs;
Array
(
[0] => 1
[1] => one
[2] => uno
)
[1] => Array
(
[0] => 2
[1] => two
[2] => dos
)
[2] => Array
(
[0] => 3
[1] => three
[2] => tres
)
[3] => Array
(
[0] => 4
[1] => four
[2] => cuatro
)
[4] => Array
(
[0] => 5
[1] => five
[2] => cinco
)
)
]]>
If the array argument contains string keys then the returned array
will contain string keys if and only if exactly one array is passed. If
more than one argument is passed then the returned array always has
integer keys.
<function>array_map</function> - with string keys
"value");
function cb1($a) {
return array ($a);
}
function cb2($a, $b) {
return array ($a, $b);
}
var_dump(array_map("cb1", $arr));
var_dump(array_map("cb2", $arr, $arr));
var_dump(array_map(null, $arr));
var_dump(array_map(null, $arr, $arr));
?>
]]>
&example.outputs;
array(1) {
[0]=>
string(5) "value"
}
}
array(1) {
[0]=>
array(2) {
[0]=>
string(5) "value"
[1]=>
string(5) "value"
}
}
array(1) {
["stringkey"]=>
string(5) "value"
}
array(1) {
[0]=>
array(2) {
[0]=>
string(5) "value"
[1]=>
string(5) "value"
}
}
]]>
&reftitle.seealso;
array_filter
array_reduce
array_walk
create_function
&seealso.callback;