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array_filter(3) [php man page]

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)

Check Out this Related Man Page

ARRAY_UDIFF_ASSOC(3)							 1						      ARRAY_UDIFF_ASSOC(3)

array_udiff_assoc - Computes the difference of arrays with additional index check, compares data by a callback function

SYNOPSIS
array array_udiff_assoc (array $array1, array $array2, [array $...], callable $value_compare_func) DESCRIPTION
Computes the difference of arrays with additional index check, compares data by a callback function. Note Please note that this function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example, array_udiff_assoc($array1[0], $array2[0], "some_comparison_func");. PARAMETERS
o $array1 - The first array. o $array2 - The second array. o $value_compare_func - The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second. int callback (mixed $a, mixed $b) RETURN VALUES
array_udiff_assoc(3) returns an array containing all the values from $array1 that are not present in any of the other arguments. Note that the keys are used in the comparison unlike array_diff(3) and array_udiff(3). The comparison of arrays' data is performed by using an user- supplied callback. In this aspect the behaviour is opposite to the behaviour of array_diff_assoc(3) which uses internal function for com- parison. EXAMPLES
Example #1 array_udiff_assoc(3) example <?php class cr { private $priv_member; function cr($val) { $this->priv_member = $val; } static function comp_func_cr($a, $b) { if ($a->priv_member === $b->priv_member) return 0; return ($a->priv_member > $b->priv_member)? 1:-1; } } $a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),); $b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),); $result = array_udiff_assoc($a, $b, array("cr", "comp_func_cr")); print_r($result); ?> The above example will output: Array ( [0.1] => cr Object ( [priv_member:private] => 9 ) [0.5] => cr Object ( [priv_member:private] => 12 ) [0] => cr Object ( [priv_member:private] => 23 ) ) In our example above you see the "1" => new cr(4) pair is present in both arrays and thus it is not in the output from the function. SEE ALSO
array_diff(3), array_diff_assoc(3), array_diff_uassoc(3), array_udiff(3), array_udiff_uassoc(3), array_intersect(3), array_inter- sect_assoc(3), array_uintersect(3), array_uintersect_assoc(3), array_uintersect_uassoc(3). PHP Documentation Group ARRAY_UDIFF_ASSOC(3)

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