ARRAY_FILTER(3) 1 ARRAY_FILTER(3)
array_filter - Filters elements of an array using a callback function
SYNOPSIS
array array_filter (array $array, [callable $callback], [int $flag])
DESCRIPTION
Iterates over each value in the $array passing them to the $callback function. If the $callback function returns true, the current value
from $array is returned into the result array. Array keys are preserved.
PARAMETERS
o $array
- The array to iterate over
o $callback
- The callback function to use If no $callback is supplied, all entries of $array equal to FALSE (see converting to boolean) will
be removed.
o $flag
- Flag determining what arguments are sent to $callback:
o ARRAY_FILTER_USE_KEY - pass key as the only argument to $callback instead of the value
o ARRAY_FILTER_USE_BOTH - pass both value and key as arguments to $callback instead of the value
RETURN VALUES
Returns the filtered array.
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.6.0 | |
| | |
| | Added optional $flag parameter and constants |
| | ARRAY_FILTER_USE_KEY and ARRAY_FILTER_USE_BOTH |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
array_filter(3) example
<?php
function odd($var)
{
// returns whether the input integer is odd
return($var & 1);
}
function even($var)
{
// returns whether the input integer is even
return(!($var & 1));
}
$array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);
echo "Odd :
";
print_r(array_filter($array1, "odd"));
echo "Even:
";
print_r(array_filter($array2, "even"));
?>
The above example will output:
Odd :
Array
(
[a] => 1
[c] => 3
[e] => 5
)
Even:
Array
(
[0] => 6
[2] => 8
[4] => 10
[6] => 12
)
Example #2
array_filter(3) without $callback
<?php
$entry = array(
0 => 'foo',
1 => false,
2 => -1,
3 => null,
4 => ''
);
print_r(array_filter($entry));
?>
The above example will output:
Array
(
[0] => foo
[2] => -1
)
Example #3
array_filter(3) with $flag
<?php
$arr = ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4];
var_dump(array_filter($arr, function($k) {
return $k == 'b';
}, ARRAY_FILTER_USE_KEY));
var_dump(array_filter($arr, function($v, $k) {
return $k == 'b' || $v == 4;
}, ARRAY_FILTER_USE_BOTH));
?>
The above example will output:
array(1) {
["b"]=>
int(2)
}
array(2) {
["b"]=>
int(2)
["d"]=>
int(4)
}
NOTES
Caution
If the array is changed from the callback function (e.g. element added, deleted or unset) the behavior of this function is unde-
fined.
SEE ALSO
array_map(3), array_reduce(3), array_walk(3).
PHP Documentation Group ARRAY_FILTER(3)