array_fill
This function filters an array and remove all null values recursively.
<?php
function array_filter_recursive($input)
{
foreach ($input as &$value)
{
if (is_array($value))
{
$value = array_filter_recursive($value);
}
}
return array_filter($input);
}
?>
Or with callback parameter (not tested) :
<?php
function array_filter_recursive($input, $callback = null)
{
foreach ($input as &$value)
{
if (is_array($value))
{
$value = array_filter_recursive($value, $callback);
}
}
return array_filter($input, $callback);
}
?>
array_filter
(PHP 4 >= 4.0.6, PHP 5)
array_filter — Filtra os elementos da array usando uma função de callback
Descrição
Itera sobre cada valor de
input passando-os para a função
callback. Se a função
callback retornar true, o valor atual de
input é retornado na matriz resultado.
Os índices das matrizes são preservados.
Parâmetros
-
input -
O array a ser iterado
-
callback -
A função callback a ser usada
Se nenhum
callbacké fornecido, todas entradas deinputiguais aFALSE(veja convertendo para booleano) serão removidas.
Valor Retornado
Retorna o array filtrado.
Exemplos
Exemplo #1 Exemplo de array_filter()
<?php
function impar($var)
{
return($var & 1);
}
function par($var)
{
return(!($var & 1));
}
$array1 = array("a" => 1, "b" => 2, "c" => 3, "d" => 4, "e" => 5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);
echo "Impares: \n";
print_r(array_filter($array1, "impar"));
echo "Pares: \n";
print_r(array_filter($array2, "par"));
?>
O exemplo acima irá imprimir:
Impares:
Array
(
[a] => 1
[c] => 3
[e] => 5
)
Pares:
Array
(
[0] => 6
[2] => 8
[4] => 10
[6] => 12
)
Exemplo #2 array_filter() sem
callback
<?php
$entry = array(
0 => 'foo',
1 => false,
2 => -1,
3 => null,
4 => ''
);
print_r(array_filter($entry));
?>
O exemplo acima irá imprimir:
Array ( [0] => foo [2] => -1 }
Notas
Cuidado
Se o array é modificado por uma função callback (e.g. elemento adicionado, deletado ou apagado) o comportamento desta função é indefinido.
Veja Também
- array_map() - Aplica uma função em todos os elementos dos arrays dados
- array_reduce() - Reduz um array para um único valor através de um processo iterativo utilizando uma função
- array_walk() - Aplica uma determinada funcão em cada elemento de um array
add a note
User Contributed Notes
array_filter - [51 notes]
romain dot lamarche at gmail dot com ¶
4 years ago
John Erck: erck0006 at junkyo dot gmail dot com ¶
1 year ago
<?php
// ARRAY FILTER RECURSIVE USING CLASS, STATIC METHOD, AND ANONYMOUS CALLBACK FUNCTION
// NOTE THAT THE CALLBACK HAS ACCESS TO BOTH THE KEY AND VALUE
// THE CLASS (FOR YOU TO COPY)
class ArrayUtil
{
public static function FilterRecursive(Array $source, $fn)
{
$result = array();
foreach ($source as $key => $value)
{
if (is_array($value))
{
$result[$key] = self::FilterRecursive($value, $fn);
continue;
}
if ($fn($key, $value))
{
$result[$key] = $value; // KEEP
continue;
}
}
return $result;
}
}
// EXAMPLE ANONYMOUS CALLBACK FUNCTION
$fn = function ($key, $value)
{
if (strpos($key, 'drop') !== FALSE)
{
return FALSE; // DROP
}
return TRUE; // KEEP
};
// EXAMPLE PRE FILTER TEST DATA
$preFilter = array(
'a' => 'one',
'b' => array(
'example_drop' => 'filter me out',
'example_keep' => 'keep me',
),
'c' => 'three',
);
// EXAMPLE USAGE CODE
echo '// print_r($preFilter);' . "\n";
print_r($preFilter);
$postFilter = ArrayUtil::FilterRecursive($preFilter, $fn);
echo "\n";
echo '// print_r($postFilter);' . "\n";
print_r($postFilter);
/* OUTPUT OPEN
// print_r($preFilter);
Array
(
[a] => one
[b] => Array
(
[example_drop] => filter me out
[example_keep] => keep me
)
[c] => three
)
// print_r($postFilter);
Array
(
[a] => one
[b] => Array
(
[example_keep] => keep me
)
[c] => three
)
OUTPUT CLOSE */
breich at reich-consulting dot net ¶
2 years ago
I built the following array_remove_keys() function to
remove one or more keys from an array.
<?php
function array_remove_keys($array, $keys = array()) {
// If array is empty or not an array at all, don't bother
// doing anything else.
if(empty($array) || (! is_array($array))) {
return $array;
}
// If $keys is a comma-separated list, convert to an array.
if(is_string($keys)) {
$keys = explode(',', $keys);
}
// At this point if $keys is not an array, we can't do anything with it.
if(! is_array($keys)) {
return $array;
}
// array_diff_key() expected an associative array.
$assocKeys = array();
foreach($keys as $key) {
$assocKeys[$key] = true;
}
return array_diff_key($array, $assocKeys);
}
// Example:
$data = array(
'name' => 'Brian',
'address1' => '98 Market St.',
'address2' => 'N/A'
);
// Output before array_remove_keys()
var_dump($data);
// Remove address2 key.
$data = array_remove_keys($data, 'address2');
// Output after array_remove_keys()
var_dump($data);
/* Output:
array(3) {
["name"]=>
string(5) "Brian"
["address1"]=>
string(13) "98 Market St."
["address2"]=>
string(3) "N/A"
}
array(2) {
["name"]=>
string(5) "Brian"
["address1"]=>
string(13) "98 Market St."
}
*/
?>
webdesign at blackbyrd dot biz ¶
3 years ago
Here's a function that will filter a multi-demensional array. This filter will return only those items that match the $value given
<?php
/*
* filtering an array
*/
function filter_by_value ($array, $index, $value){
if(is_array($array) && count($array)>0)
{
foreach(array_keys($array) as $key){
$temp[$key] = $array[$key][$index];
if ($temp[$key] == $value){
$newarray[$key] = $array[$key];
}
}
}
return $newarray;
}
?>
Example:
<?php
$results = array(
0 => array('key1' => '1', 'key2' => 2, 'key3' => 3),
1 => array('key1' => '12', 'key2' => 22, 'key3' => 32)
);
$nResults = filter_by_value($results, 'key2', '2');
?>
Output :
array(
0 => array('key1' => '1', 'key2' => 2, 'key3' => 3)
);
Alix Axel ¶
8 days ago
If you need this function to return falsy results (like "0"), yet discard truly empty ones (that have a 0 string length, like null, false, ''), you can use strlen() as the callback:
<?php
array_filter($array, 'strlen');
?>
espertalhao04 at hotmail dot com ¶
1 month ago
breich at reich-consulting dot net made an awesome function, but it has a poor performance, and is bloated.
here is a shorter version:
<?php
function array_remove_keys($array, $keys = array(), $callback=null) {
if(empty($array) || (! is_array($array))) {
return $array;
}
if(is_string($keys) && !is_array($keys=explode(',',$keys)))
{
return $array;
}
foreach($keys as $key) {
$key=trim($key,' ');
if(!$callback || !$callback($array[$key],$key))
unset($array[$key]);
}
return $array;
}
?>
i decided to let here stay 2 conditions, even though they can be rewritten to 1.
unsetting is faster than array_diff_keys.
sometimes, people separate strings like 'a, b, c' or 'a , b , c'...
i added support for those, since they are essentially the same list.
i also added a callback option, which you specify a function and it will give the value and the key to it.
p.s.: php uses short-circuit evaluation. example:
!$callback || !$callback($array[$key],$key)
if $callback is empty, it doesn't try to run $callback().
why?
because !$callback || !$callback($array[$key],$key) will be true, no matter the value of !$callback().
so, to save resources and time, php jumps if !$callback is true
tx at tshwarelo-leaka dot co dot za ¶
1 month ago
To get rid of all white space in an array without looping.
<?php
$array = array(5, " ", 2, NULL, 13, "", 7, "\n", 4, "\t");
print_r($array);
$result = array_filter($array, create_function('$a','return preg_match("#\S#", $a);'));
print_r($result);
?>
Array
(
[0] => 5
[1] =>
[2] => 2
[3] =>
[4] => 13
[5] =>
[6] => 7
[7] =>
[8] => 4
[9] =>
)
Array
(
[0] => 5
[2] => 2
[4] => 13
[6] => 7
[8] => 4
)
Craig ¶
4 years ago
I wanted a function to keep the values that were filtered out and return them separately. Basically, split the array by some callback. I wrote this for the job:
<?php
function array_split($input, &$trues, &$falses, $compare)
{
while (($item = array_pop($input)) != NULL)
{
if ($compare($item)) $trues[] = $item;
else $falses[] = $item;
}
}
?>
very simple, something I would think would be standard, and array_filter would amount to discarding the falses.
Hayley Watson ¶
5 years ago
Just a simplification of my function from last month.
<?php
function partition($input, $callback=null)
{
if(is_null($callback))
$true = array_filter($input);
else
$true = array_filter($input, $callback);
$false = array_diff_key($input, $true);
}
?>
leon at darkk dot net dot ru ¶
5 years ago
Here is a way to get customizable filter
<?php
function blablabla() {
....
$new = getNewUidls();
class UidlFilter {
function UidlFilter($uidls) { $this->uidls = $uidls; }
function filter($metamsg) { return in_array($metamsg['uidl'], $this->uidls); }
}
$msglist = array_filter($msglist, array(new UidlFilter($new), 'filter');
....
}
?>
marc dot vanwoerkom at fernuni-hagen dot de ¶
8 years ago
Some of PHP's array functions play a prominent role in so called functional programming languages, where they show up under a slightly different name:
<?php
array_filter() -> filter(),
array_map() -> map(),
array_reduce() -> foldl() ("fold left")
?>
Functional programming is a paradigm which centers around the side-effect free evaluation of functions. A program execution is a call of a function, which in turn might be defined by many other functions. One idea is to use functions to create special purpose functions from other functions.
The array functions mentioned above allow you compose new functions on arrays.
E.g. array_sum = array_map("sum", $arr).
This leads to a style of programming that looks much like algebra, e.g. the Bird/Meertens formalism.
E.g. a mathematician might state
map(f o g) = map(f) o map(g)
the so called "loop fusion" law.
Many functions on arrays can be created by the use of the foldr() function (which works like foldl, but eating up array elements from the right).
I can't get into detail here, I just wanted to provide a hint about where this stuff also shows up and the theory behind it.
Anonymous ¶
4 months ago
If you want a quick way to remove NULL, FALSE and Empty Strings (""), but leave values of 0 (zero), you can use the standard php function strlen as the callback function:
eg:
<?php
// removes all NULL, FALSE and Empty Strings but leaves 0 (zero) values
$result = array_filter( $array, 'strlen' );
?>
niehztog ¶
4 years ago
In case you are interested (like me) in filtering out elements with certain key-names, array_filter won't help you. Instead you can use the following:
<?php
$arr = array( 'element1' => 1, 'element2' => 2, 'element3' => 3, 'element4' => 4 );
$filterOutKeys = array( 'element1', 'element4' );
$filteredArr = array_diff_key( $arr, array_flip( $filterOutKeys ) )
?>
Result will be something like this:
['element2'] => 2
['element3'] => 3
lisachenko dot it at HUMAN dot gmail dot com ¶
1 year ago
You can access the current key of array by passing a reference to array into callback function and call key() and next() method in the callback function:
<?php
$data = array('first' => 1, 'second' => 2, 'third' => 3);
$data = array_filter($data, function ($item) use (&$data) {
echo "Filtering key ", key($data), '<br>', PHP_EOL;
next($data);
return false;
});
?>
However be careful with array internal pointer or use reset() method before calling array_filter().
chrisstocktonaz at gmail dot com ¶
4 years ago
I use the following to see if a array consist of scalar values or null, but of course you could mix it up using any of the is_ functions.
<?php
if(count($data) !== count(array_filter($data, 'is_scalar') + array_filter($data, 'is_null'))) {
throw new Exception('Array did not consist of scalar and null values');
}
?>
quecoder at gmail ¶
4 years ago
// my implementation for array_filter
function my_array_filter($array,$function,$preserve=true)
{
$return = array();
foreach ($array as $k=>$v)
{
if($function($v)==true) $return[$k]=$v;
}
if($preserve) return $return;
else return array_values($return);
}
function odd($value)
{
return ($value & 1);
}
$oddonly = array (1,2,3,4,5,6,7,8,9);
print_r(my_array_filter($oddonly,'odd',1));
//output
//Array ( [0] => 1 [2] => 3 [4] => 5 [6] => 7 [8] => 9 )
//Khaled Mohammed
rolf at example dot com ¶
2 years ago
Here is how you could easily delete a specific value from an array with array_filter:
<?php
$array = array (1, 3, 3, 5, 6);
$my_value = 3;
$filtered_array = array_filter($array, function ($element) use ($my_value) { return ($element != $my_value); } );
print_r($filtered_array);
?>
output:
Array
(
[0] => 1
[3] => 5
[4] => 6
)
sami ¶
4 years ago
Yes, it may remove NULLS, but it also removes anything that factors to a FALSE as well; like FALSE and ZERO. :/
ajohnson at speakeasy dot org ¶
10 years ago
I was looking for a function to delete values from an array and thought I had found it in array_filter(), however, I *didn't* want the keys to be preserved *and* I needed blank values cleaned out of the array as well. I came up with the following (with help from many of the above examples):
<?php
function array_delete($array, $filterfor){
$thisarray = array ();
foreach($array as $value)
if(stristr($value, $filterfor)===false && strlen($value)>0)
$thisarray[] = $value;
return $thisarray;
}
$array1 = array ('OtHeR','this', 'that', 'Other','', 9, 101, 'fifty', 'other','','');
echo "<pre>array :\n";
print_r($array1);
$array2=array_delete($array1, "Other");
echo "filtered:\n";
print_r($array2);
?>
xert ¶
8 years ago
According to a simple test with array_filter($array) and array_diff($array, array('')) is array_filter 2.5 times faster than array_diff when deleting empty entries.
g dot kuizinas at anuary dot com ¶
1 month ago
<?php
function array_filter_recursive ($data) {
$original = $data;
$data = array_filter($data);
$data = array_map(function ($e) {
return is_array($e) ? array_filter_recursive($e) : $e;
}, $data);
return $original === $data ? $data : array_filter_recursive($data);
}
$data = ['a' => 0, 'b' => [], 'c' => [[]], 'd' => [[[[]]]], 'e' => 'foo', 'f' => [[['a']]], [true], [[],['a'], [true, false]]];
$data = array_filter_recursive($data);
?>
Anonymous ¶
1 month ago
If you're looking to filter an associative array to leave out certain keys, this is not the function to do it.
/*
* Simple example illustrating how to filter an associative array so as to exclude certain keys in the resulting array
*/
$array1 = array( 'a' => 1, 'b' => 2, 'c' => 3 );
// let's strip out the keys 'c' and 'b'
var_dump(
array_diff_key( $array1, array_flip( array( 'b', 'c' ) ) )
);
jtreminio at gmail dot com ¶
7 months ago
You can use array_filter from within a class to access a protected method from that same class:
<?php
class Bar {
public function foo()
{
$array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
print_r(array_filter($array1, array($this, 'naz')));
}
protected function baz($var)
{
return($var & 1);
}
}
$bar = new Bar();
$bar->foo();
?>
spam dot 2011 at rebell dot at ¶
1 year ago
If you have not noticed already - array_filter() can be used to remove empty elements, since an empty string considered "false", if you not specify a callback
Keep in mind, that this will remove also some other values - so if you want a quick "remove empty elements from array" this function will be fine, as long as you dont have anything to keep, which casts to "false"
Peter Robinett ¶
2 years ago
Because array_filter() preserves keys, you should consider the resulting array to be an associative array even if the original array had integer keys for there may be holes in your sequence of keys. This means that, for example, json_encode() will convert your result array into an object instead of an array. Call array_values() on the result array to guarantee json_encode() gives you an array.
acid24 at gmail dot com ¶
2 years ago
A function that allows filtering an array by keys:
<?php
function array_filter_key( $input, $callback ) {
if ( !is_array( $input ) ) {
trigger_error( 'array_filter_key() expects parameter 1 to be array, ' . gettype( $input ) . ' given', E_USER_WARNING );
return null;
}
if ( empty( $input ) ) {
return $input;
}
$filteredKeys = array_filter( array_keys( $input ), $callback );
if ( empty( $filteredKeys ) ) {
return array();
}
$input = array_intersect_key( array_flip( $filteredKeys ), $input );
return $input;
}
?>
Example:
<?php
$input = array_flip( range( 'a', 'z' ) );
$consonants = array_filter_key( $arr, function( $elem ) {
$vowels = "aeiou";
return strpos( $vowels, strtolower( $elem ) ) === false;
} );
?>
Outputs:
array(21) {
["b"]=>
int(1)
["c"]=>
int(2)
["d"]=>
int(3)
["f"]=>
int(5)
["g"]=>
int(6)
["h"]=>
int(7)
["j"]=>
int(9)
["k"]=>
int(10)
["l"]=>
int(11)
["m"]=>
int(12)
["n"]=>
int(13)
["p"]=>
int(15)
["q"]=>
int(16)
["r"]=>
int(17)
["s"]=>
int(18)
["t"]=>
int(19)
["v"]=>
int(21)
["w"]=>
int(22)
["x"]=>
int(23)
["y"]=>
int(24)
["z"]=>
int(25)
}
Ant P. ¶
3 years ago
If you're using filter_input_array, the values will be null on failure and anything else on success. Because array_filter by default removes false, 0 and "" you need to do extra work like this:
<?php
$input_array = filter_input_array(INPUT_GET, array(
'var1' => FILTER_VALIDATE_BOOLEAN,
'var2' => FILTER_VALIDATE_INT
));
array_filter($input_array, function($a) { return !is_null($a) });
?>
mewsterus at yahoo dot com ¶
3 years ago
Here's an easy way to get a combination of keys and values, such that if you don't specify a key you will get the value, and if you do specify a key you will get the key:
<?php
$array = array('One' => 'First', 'Second', 'Third', 'Four' => 'Fourth', 'Fifth');
var_dump(array_keys($array));
$names = array_filter(array_keys($array), 'is_string') + array_values($array);
ksort($array);
var_dump($names);
?>
Outputs:
array(5) {
[0]=>string(3) "One"
[1]=>int(0)
[2]=>int(1)
[3]=>string(4) "Four"
[4]=>int(2)
}
array(5) {
[0]=>string(3) "One"
[1]=>string(6) "Second"
[2]=>string(5) "Third"
[3]=>string(4) "Four"
[4]=>string(5) "Fifth"
}
Without using ksort, the keys appear before the fallback values, instead of inline and appearing like they replace them, however the keys are intact (which is why ksort works) so it's only execution order.
darren at dazwin dot com ¶
4 years ago
Regarding comment about trimming empty strings, the code posted will get into an infinite loop if the array is reduced to zero elements. The following might be better:
<?php
function array_trim($array) {
while (!empty($array) and strlen(reset($array)) === 0) {
array_shift($array);
}
while (!empty($array) and strlen(end($array)) === 0) {
array_pop($array);
}
return $array;
}
?>
WASD ¶
4 years ago
You can easily delete all NULL elements from array with following statement:
<?php
$arr = array_filter($arr);
?>
Martin ¶
5 years ago
This function trims empty strings from the beginning and end of an array.
It's useful when outputing plaintext files on a page and you want to skip empty lines at the beginning and end, but not within the text.
<?php
function array_trim($array) {
while (strlen(reset($array)) === 0) {
array_shift($array);
}
while (strlen(end($array)) === 0) {
array_pop($array);
}
return $array;
}
?>
You might want to trim each element too.
Hayley Watson ¶
5 years ago
Here is my own version of Renee Sarsoo's array_split() function; given an array and a callback it returns two arrays, in which the first contains elements that passed the filter and the second contains elements that didn't. (If no callback is passed, the first array contains the nonempty elements, as you'd get from array_filter() if you don't give it a callback). Array keys are preserved.
<?php
function partition($input, $callback=null)
{
static $not_empty=null;
if(is_null($not_empty))
$not_empty = create_function('$o', 'return !empty($o);');
if(is_null($callback)) $callback = $not_empty;
$true = array_filter($input, $callback);
$false = array_diff_key($input, $true);
return array($true, $false);
}
?>
Fladnag - bahatest at ifrance dot com ¶
6 years ago
If you have a form with multiple checkbox having ID element as value for selection in a list, you probably have a SQL request like :
$req="SELECT ... WHERE ID IN (".implode(',', array_keys($choices)).")";
without quote before and after choices keys because they are numeric values... but in fact, they can be string values, and a SQL injection problem.
with array_filter, you can easily filter bad values :
<?php
$choices=array('A'=>'on', -1=>'on', 0=>'on', 1=>'on', 12=>'on', "1)or 1=1--"=>'on');
print_r($choices);
$choices=array_filter(array_keys($choices), 'is_numeric');
print_r($choices);
?>
will print :
<?php
Array
(
[A] => on
[-1] => on
[0] => on
[1] => on
[12] => on
[1)or 1=1--] => on
)
Array
(
[1] => -1
[2] => 0
[3] => 1
[4] => 12
)
?>
Maxwel Leite ¶
9 years ago
For any type of array. Basead in redshift code.
<?php
function array_clean ($array, $todelete = false, $caseSensitive = false) {
foreach($array as $key => $value) {
if(is_array($value)) {
$array[$key] = array_clean($array[$key], $todelete, $caseSensitive);
}
else {
if($todelete) {
if($caseSensitive) {
if(strstr($value ,$todelete) !== false)
unset($array[$key]);
}
else {
if(stristr($value, $todelete) !== false)
unset($array[$key]);
}
}
elseif (empty($value)) {
unset($array[$key]);
}
}
}
return $array;
}
?>
Jeremy ¶
9 years ago
Here is a nice little function which will apply a callback function recursively over a multidimensional array. If the callback function returns false, then it replaces the value of the array with $filtered_ouput. This function gracefully handles objects inside of arrays (and objects within objects within arrays, etc). It is specifically designed for your callback function to process on the array key's (unlike normal array_filter which filters on the values), but it could work on the array values depending on your test criteria (YMMV).
<?PHP
function array_key_filter_multi($array, $callback, $filtered_output = "")
{
$ret = array();
foreach($array as $key=>$value) {
if($callback($key,$value)) {
if(is_array($value)) {
$ret[$key] = array_key_filter_multi($value, $callback, $filtered_output);
}
elseif(is_object($value)) {
$ret[$key] = array_key_filter_multi(get_object_vars($value), $callback, $filtered_output);
}
else {
$ret[$key]=$value;
}
}
else {
$ret[$key]=$filtered_output;
}
}
return $ret;
}
?>
We use this to filter redundant data from debugging output. An example usage is:
<?
$callback_func = create_function('$key, $value', 'return ($key == "db" || $key == "smarty") ? false : true;');
echo "<PRE>" . print_r(array_key_filter_multi($_SESSION, $callback_func, "**filtered by function**"), true) . "</PRE>";
?>
Which filters all keys with "db" or "smarty" as their name (including objects which have a reference to those variables). The output of the above in a test case I did is the following:
Array
(
[userdata] => Array
(
[sid] => a130e675d380e0e9fe47897922d719ac
[not_in_db] =>
[user_id] => 1
[session_id] => 154
[permissions] => 1
[username] => tester
)
[systemobjects] => Array
(
[db] => **filtered by function**
[smarty] => **filtered by function**
)
)
redshift at pandora dot be ¶
9 years ago
Hi all,
Here's a function that will look trough an array, and removes the array member when the search string is found.
<?php
function array_clean ($input, $delete = false, $caseSensitive = false)
{
$i = 0;
while($i < count($input))
{
if($delete)
{
if($caseSensitive)
{
if(!strstr($input[$i] ,$delete))
{
$return[] = $input[$i];
}
}
else
{
if(!stristr($input[$i], $delete))
{
$return[] = $input[$i];
}
}
}
else
{
if(!empty($input[$i]))
{
$return[] = $input[$i];
}
}
$i++;
}
return $return;
}
?>
array array_clean(array input [, string needle [, boolean case sensitive]])
if needle is left empty, the function will delete the array members that have no value (this means if it's empty).
NOTE: It rebuilds the array from scratch, so keys begin with 0, like you would create a new array.
Example:
$array = array("John", "Doe", "Macy");
$array = array_clean($array, "doe", false);
print_r($array);
would return:
array
(
[0] => John
[1] => Macy
)
Hopes this helps someone :-)
skd2 at ece dot msstate dot edu ¶
10 years ago
The following function modifies the supplied array recursively so that filtering is performed on multidimentional arrays as well, while preserving keys.
<?php
function array_cleanse(&$arr){
$temp = array();
reset($arr);
if(count($arr) == 0) return "";
foreach($arr as $key=>$val):
(is_array($val))? array_cleanse($val) : NULL;
($val)? $temp[$key] = $val : NULL;
endforeach;
$arr = $temp;
reset($arr);
}
?>
$arr1 = array('a'=>20,'b'=>array(''),'c'=>array(1,0,2),'d'=>0);
array_cleanse($arr1);
$arr1 will be array('a'=>20,'c'=>array(1,2))
array_filter may not be used as it does not modify the array within itself.
ajohnson at speakeasy dot org ¶
10 years ago
be careful with the above function "array_delete"'s use of the stristr function, it could be slightly misleading. consider the following:
<?php
function array_delete($array, $filterforsubstring){
$thisarray = array ();
foreach($array as $value)
if(stristr($value, $filterforsubstring)===false && strlen($value)>0)
$thisarray[] = $value;
return $thisarray;
}
function array_delete2($array, $filterforstring, $removeblanksflag=0){
$thisarray = array ();
foreach($array as $value)
if(!(stristr($value, $filterforstring) && strlen($value)==strlen($filterforstring))
&& !(strlen($value)==0 && $removeblanksflag))
$thisarray[] = $value;
return $thisarray;
}
function array_delete3($array, $filterfor, $substringflag=0, $removeblanksflag=0){
$thisarray = array ();
foreach($array as $value)
if(
!(stristr($value, $filterfor)
&& ($substringflag || strlen($value)==strlen($filterfor))
)
&& !(strlen($value)==0 && $removeblanksflag)
)
$thisarray[] = $value;
return $thisarray;
}
$array1 = array ('the OtHeR thang','this', 'that', 'OtHer','', 9, 101, 'fifty', ' oTher', 'otHer ','','other','Other','','other blank things');
echo "<pre>array :\n";
print_r($array1);
$array2=array_delete($array1, "Other");
echo "array_delete(\$array1, \"Other\"):\n";
print_r($array2);
$array2=array_delete2($array1, "Other");
echo "array_delete2(\$array1, \"Other\"):\n";
print_r($array2);
$array2=array_delete2($array1, "Other",1);
echo "array_delete2(\$array1, \"Other\",1):\n";
print_r($array2);
$array2=array_delete3($array1, "Other",1);
echo "array_delete3(\$array1, \"Other\",1):\n";
print_r($array2);
$array2=array_delete3($array1, "Other",0,1);
echo "array_delete3(\$array1, \"Other\",0,1):\n";
print_r($array2);
?>
mchargue at usc dot edu ¶
3 years ago
Wanting to pass an additional to parameter to the callback function? This worked for me, there's probably another way to accomplish this task but just so you see how it can be done. (I actually used this technique to strip old dates out of an array) :
<?php
//define in global scope so functions can access
$var_to_pass = null;
function myfilter($input_var_outer,$param) {
global $var_to_pass;
$var_to_pass = $param;
function mycallback($input_var_inner) {
global $var_to_pass;
return ($input_var_inner>$var_to_pass) ? true : false;
}
$return_arr = array_filter($input_var_outer,'mycallback');
//re-key if you want
$return_arr = array_merge(array(),$return_arr);
return $return_arr;
}
$min = 5;
$a = array(1,3,5,7,9);
//remove elements from array that are not greater than $min
$a = myfilter($a,$min);
echo "<pre>";
print_r($a);
echo "</pre>";
?>
--
Output:
Array
(
[0] => 7
[1] => 9
)
nat at fishtrap dot co dot uk ¶
4 years ago
One of the nice things about this function is that you can a standard php function such as is_string
e.g.
<?php
$input =array(1 , '2', 'three', array('sausages'));
$result = array_filter($input ,'is_string');
print_r($result);
?>
Result will be
Array
(
[1] => 2
[2] => three
)
Joan Garnet ¶
5 years ago
Be careful with this function as it preserves array indexes after applying the filter:
<?php
function f( $item ){
return $item < 50;
}
print_r( array_filter(array( 10, 100, 20 ),"f") );
/* OUTPUT
Array
(
[0] => 10
[2] => 20
)*/
?>
You can easily reassign indexes like this:
<?php
function f( $item ){
return $item < 50;
}
print_r( array_values(array_filter(array( 10, 100, 20 ),"f")) );
/* OUTPUT
Array
(
[0] => 10
[1] => 20
)*/
?>
Rene Saarsoo ¶
5 years ago
Sometimes you want to do something with elements you have filtered out and something else with other elements. So instead of filtering elements out to one array you would like to split array into two parts:
<?php
/**
* Splits array into two arrays using a callback function
*
* It is like array_filter(), but instead of one array, two arrays are returned:
* first one with elements for which the callback function evaluates to true,
* and second one, for which it evaluates to false.
*
* If no callback is supplied, all entries of input equal to FALSE will be removed.
*
* Array keys are preserved.
*
* @param $callback the callback function to use
* @return array(truth_array, false_array)
*/
function array_split($input, $callback=null) {
$callback = isset($callback) ? $callback : create_function('$x', 'return $x == true;');
$true = array();
$false = array();
foreach ($input as $key => $value) {
if (call_user_func($callback, $value)) {
$true[$key] = $value;
}
else {
$false[$key] = $value;
}
}
return array($true, $false);
}
?>
klaproth at creative-mindworks dot de ¶
6 years ago
As long as the array's keys are irrelevant, there is a simple way to remove blank values from the array, after filtering has been applied. The following example is used to remove all strings from an array that have a length of less than 4 characters.
<?php
function validElement($element) {
return strlen($element) > 3;
}
$filtered_array = array_values(array_filter($input_array, "validElement"));
?>
ydotzhangatwriwindberdotorg ¶
7 years ago
I have written a function that will filter an array by the frequency of
element value in the array. This may be useful to some people.
<?php
/////////////////////////////////////////////////////////////////
// Filter an array by value freguebcy
// Input: $array
// cut-off: $frequency (>=1)
// result option option: 1=$frequency and higher
// 0=$frequency only
// -1=$frequency and lower
/////////////////////////////////////////////////////////////////
function filter_array($array, $frequency = 2, $include = 1){
$freg = array_count_values($array);
if($frequency<1){
print "** frequency cut-off should be >= 1! **\n";
return false;
}
foreach($freg as $k => $v){
if($include == 0){
if($frequency != $v){
$freg[$k] = 0;
}
}elseif($include > 0){
if($frequency > $v){
$freg[$k] = 0;
}
}else{
if($frequency < $v){
$freg[$k] = 0;
}
}
}
$filtered = array_filter($freg);
$values = array_keys($filtered);
return array_intersect($array,$values);
}
?>
steven at xinu dot org ¶
9 years ago
The anonymous fellow a few posts up was trying to illustrate how to use the array_filter() function with class methods but confused things a bit. Here's a cleaner example:
<?php
class testclass
{
function testclass()
{
// define the numbers array
$numbers = array(1, 2, 3, 4, 5, 6);
// pull out the odd numbers
$odd = array_filter($numbers, array($this, "odd"));
// pull out the even numbers
$even = array_filter($numbers, array($this, "even"));
}
function odd($var)
{
return($var % 2 == 1);
}
function even($var)
{
return($var % 2 == 0);
}
}
?>
Anonymous ¶
10 years ago
You cannot do this:
$non_empty_array = array_filter($original_array, 'empty');
Since empty() is not a function but a language construct. (http://www.php.net/manual/en/function.empty.php)
Anonymous ¶
10 years ago
I was looking for a function able to take some values out of an array iteratively, and found array_filter very useful although i had some trouble figuring out the proper syntax...
<?php
class someclass {
var $current;
/** this is our iterative function */
function main ($variable,$array){
if (end test){
return true;
}
$variable= some treatment...
if (in_array($variable, $array)){
$this->current=something...($variable);
// this is the not-well-documented part
$array=$array_filter($array, array($this, "array_reduce");
}
$this->main($variable, $array);
}
/** this is the function used to filter */
function reduce_list($var){
return ($var!=$this->current);
}
}
?>
sam,pointsystems,com ¶
11 years ago
Here's a good function to filter multidimensional arrays:
<?php
function array_filter_multi($input, $filter="", $keepMatches=true) {
if (!is_array($input))
return ($input==$filter xor $keepMatches==false) ? $input : false;
while (list ($key,$value) = @each($input)){
$res = array_filter_multi($value, $filter,$keepMatches);
if ($res !== false)
$out[$key] = $res;
}
return $out;
}
?>
Default behavior is to remove blanks from a multi-dimensional array, but you can filter out any string (arg #2) with a positive or negative filter (arg #3).
noonesvk at gmail dot com ¶
2 years ago
Hi all,
I made a simple reindex & filter function.
reindex( array $input, [ $blacklist = array() ] )
This function is working only with array that has keys in INTEGER.
<?php
function reindex(array $source, $blacklist = array())
{
$i = 0;
foreach ($source as $key => $val) {
if ($key != $i) {
unset($source[$key]);
$source[$i] = $val;
}
$i++;
}
foreach ($source as $key => $val) {
foreach ($blacklist as $var) {
if ($val === $var) {
unset($source[$key]);
$source = reindex($source, $blacklist);
}
}
}
return $source;
}
// Examples:
// Create a simple array
$input = array(1 => 'red', 3 => 'green', 5 => 'blue', 7 => TRUE, 9 => FALSE, 11 => NULL);
// NOTE: If you have an array (look above) and your blacklist will look like this: array(TRUE, FALSE, NULL)
// Filter will delete array keys with value TRUE, FALSE or NULL
$blacklist = array(TRUE, FALSE, NULL);
// Output is: Array ( [0] => red [1] => green [2] => blue )
print_r( reindex($input, $blacklist) );
?>
If you don't want to filter array by keys in blacklist, just use this prototype: reindex( array $input ), it should be fine. :)
If you guys have question, feel free to contact me. Have a nice day.
marijnk at NOSPAM dot gwobbel dot com ¶
4 years ago
I was looking for a function that could filter values from an array using a regular expression pattern supplied, based on leon at darkk dot net dot ru I created the following:
Description:
Return array of matching values from array using regular expression.
<?php
class array_ereg {
function array_ereg($pattern) { $this->pattern = $pattern; }
function ereg($string) {
return ereg($this->pattern, $string);
}
}
?>
Usage :
<?php
$matches = array_filter($subject, array(new array_ereg($pattern), 'ereg'));
?>
Example:
<?php
$subject = array ("Thumbs.db", "image001.png", "image001.jpg", "image002.png");
print_r(array_filter($subject, array(new array_ereg("image[0-9]{3}\.png"), 'ereg')));
?>
Outputs:
Array ( [1] => image001.png [3] => image002.png )
nospam at jcornelius dot com ¶
5 years ago
Don't forget that using callbacks in a class requires that you reference the object name in the callback like so:
<?php
$newArray = array_filter($array, array($this,"callback_function"));
?>
Where "$this" is the reference to your object.