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.
The array to iterate over
The callback function to use
If no callback
is supplied, all entries of array
equal to FALSE
(see converting to boolean) will be removed.
Flag determining what arguments are sent to callback
:
-
ARRAY_FILTER_USE_KEY
- pass key as the only argument tocallback
instead of the value -
ARRAY_FILTER_USE_BOTH
- pass both value and key as arguments tocallback
instead of the value
Returns the filtered array.
Added optional flag
parameter and constants ARRAY_FILTER_USE_KEY
and ARRAY_FILTER_USE_BOTH
<?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); $array2 = array(6, 7, 8, 9, 10, 11, 12); echo "Odd :\n"; print_r(array_filter($array1, "odd")); echo "Even:\n"; 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 )
<?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 )
<?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) }
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