array_filter

(PHP 4 = 4.0.6)

array_filter -- Filters elements of an array using a callback function

Description

array array_filter ( array input [, callback function])

array_filter() returns an array containing all the elements of input filtered according a callback function. If the input is an associative array the keys are preserved.

範例 1. array_filter() example

function odd($var) {
    return ($var % 2 == 1);
}

function even($var) {
    return ($var % 2 == 0);
}

$array1 = array ("a"= 1, "b"= 2, "c"= 3, "d"= 4, "e"= 5);
$array2 = array (6, 7, 8, 9, 10, 11, 12);

echo "Odd :\n";
print_r(array_filter($array1, "odd"));
echo "Even:\n";
print_r(array_filter($array2, "even"));

The printout of the program above will be:

Odd :
Array
(
    [a] =  1
    [c] =  3
    [e] =  5
)
Even:
Array
(
    [0] =  6
    [2] =  8
    [4] =  10
    [6] =  12
)




Users may not change the array itself from the callback function. e.g. Add/delete an element, unset the array that array_filter() is applied to. If the array is changed, the behavior of this function is undefined.

See also array_map() and array_reduce().