It's worth nothing that array_walk can not be used to change keys in the array.
The function may be defined as (&$value, $key) but not (&$value, &$key).
Even though PHP does not complain/warn, it does not modify the key.
array_walk
(PHP 4, PHP 5, PHP 7, PHP 8)
array_walk — Exécute une fonction fournie par l'utilisateur sur chacun des éléments d'un tableau
Description
Exécute la fonction callback définie par l'utilisateur
sur chaque élément du tableau array.
array_walk() n'est pas affecté par le pointeur interne
du tableau array.
array_walk() traversera le tableau en totalité
sans se soucier de la position du pointeur.
Liste de paramètres
-
array -
Le tableau d'entrée.
-
callback -
Typiquement,
callbackprend deux paramètres. La valeur du paramètrearrayétant le premier et la clé/index, le second.Note:
Si
callbackdoit travailler avec les véritables valeurs du tableau, spécifiez que le premier paramètre decallbackdoit être passé par référence. Alors, les éléments seront directement modifiés dans le tableau.Note:
Plusieurs fonctions internes (par exemple, strtolower()) émettent une alerte si plus d'arguments que ceux attendus sont passés à la fonction et ne sont pas utilisables directement comme
callback.Seules les valeurs du
arraypeuvent être modifiées ; sa structure ne peut pas, c'est-à-dire que vous ne pouvez ajouter, supprimer ou réordonner des éléments. Si la fonction de callback ne respecte pas cette règle, le comportement va devenir indéfini et imprévisible. -
arg -
Si le paramètre optionnel
argest fourni, il sera passé comme troisième paramètre à la fonction définie par l'utilisateurcallback.
Valeurs de retour
Retourne true.
Erreurs / Exceptions
À partir de PHP 7.1.0, un ArgumentCountError
sera levé si la fonction callback requiert plus
de 2 paramètres (la valeur et la clé de l'élément du tableau),
ou plus de 3 si arg est aussi fournit.
Précédemment, dans ce cas une erreur de niveau
E_WARNING
aurait été générée à chaque fois que la fonction
array_walk() appelle callback.
Historique
| Version | Description |
|---|---|
| 8.0.0 |
Si callback attend que le deuxième ou troisième
paramètre soit passé par référence, cette fonction émet désormais
une E_WARNING.
|
Exemples
Exemple #1 Exemple avec array_walk()
<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
function test_alter(&$item1, $key, $prefix)
{
$item1 = "$prefix: $item1";
}
function test_print($item2, $key)
{
echo "$key. $item2\n";
}
echo "Avant ...:\n";
array_walk($fruits, 'test_print');
array_walk($fruits, 'test_alter', 'fruit');
echo "... et après :\n";
array_walk($fruits, 'test_print');
?>L'exemple ci-dessus va afficher :
Avant ...: d. lemon a. orange b. banana c. apple ... et après : d. fruit: lemon a. fruit: orange b. fruit: banana c. fruit: apple
Exemple #2 Exemple de array_walk() avec l'utilisation d'une fonction anonyme
<?php
$elements = ['a', 'b', 'c'];
array_walk($elements, function ($value, $key) {
echo "{$key} => {$value}\n";
});
?>L'exemple ci-dessus va afficher :
0 => a 1 => b 2 => c
Voir aussi
- array_walk_recursive() - Applique une fonction de rappel récursivement à chaque membre d'un tableau
- iterator_apply() - Appelle une fonction pour tous les éléments d'un itérateur
- list() - Assigne des variables comme si elles étaient un tableau
- each() - Retourne chaque paire clé/valeur d'un tableau
- call_user_func_array() - Appelle une fonction de rappel avec les paramètres rassemblés en tableau
- array_map() - Applique une fonction sur les éléments d'un tableau
- foreach
add a note
User Contributed Notes 37 notes
bisqwit at iki dot fi ¶
20 years ago
ezhacher at gmail dot com ¶
10 years ago
Calling an array Walk inside a class
If the class is static:
array_walk($array, array('self', 'walkFunction'));
or
array_walk($array, array('className', 'walkFunction'));
Otherwise:
array_walk($array, array($this, 'walkFunction'));
01001coder at gmail dot com ¶
6 years ago
I noticed that :
PHP ignored arguments type when using array_walk() even if there was
declare(strict_types=1) .
See this code as an example ...
<?php
declare(strict_types=1);
$fruits = array("butter" => 5.3, "meat" => 7, "banana" => 3);
function test_print(int $item2, $key) {
echo "$key: $item2<br />\n";
}
array_walk($fruits, 'test_print');
?>
The output is :
butter: 5
meat: 7
banana: 3
whilst the expecting output is :
Fatal error: Uncaught TypeError: Argument 1 passed to test_print() must be of the type integer
because "butter" => 5.3 is float
I asked someone about it and they said "this was caused by the fact that callbacks called from internal code will always use weak type". But I tried to do some tests and this behavior is not an issue when using call_user_func().
fred ¶
8 years ago
Correction for the speed test from zlobnygrif.
<?php
// Test results
$array1 = test('array_walk');
$array2 = test('array_walk_list_each');
$array3 = test('array_walk_foreach1');
$array4 = test('array_walk_foreach2');
// Check arrays for equal
var_dump($array1 == $array2, $array1 == $array3, $array1 == $array4);
// Test function 1
function array_walk_list_each(&$array, $function, $userData = null) {
/* make sure we walk the array each time */
reset($array);
while ( list($key, $value) = each($array) )
$function($array[$key], $key, $userData);
}
// Test function 2
function array_walk_foreach1(&$array, $function, $userData = null) {
foreach ($array as $key => &$value )
$function($value, $key, $userData);
}
// Test function 3
function array_walk_foreach2(&$array, $function, $userData = null) {
foreach ($array as $key => $value )
$function($array[$key], $key, $userData);
}
function some_function(&$value, $key, $userData) {
$value = "$key => $userData";
}
function test($function, $count = 10000, $arrayElements = 1000) {
echo $function, ' ... ';
$array = array_fill(0, $arrayElements, "some text value");
$timer = microtime(true);
for( $i = 0; ++$i < $count; )
/* change data for each $i */
$function($array, 'some_function', 'some user data ' . $i);
printf("%.3f sec\n", microtime(true) - $timer);
return $array;
}
ludvig dot ericson at gmail dot com ¶
18 years ago
In response to 'ibolmo', this is an extended version of string_walk, allowing to pass userdata (like array_walk) and to have the function edit the string in the same manner as array_walk allows, note now though that you have to pass a variable, since PHP cannot pass string literals by reference (logically).
<?php
function string_walk(&$string, $funcname, $userdata = null) {
for($i = 0; $i < strlen($string); $i++) {
# NOTE: PHP's dereference sucks, we have to do this.
$hack = $string{$i};
call_user_func($funcname, &$hack, $i, $userdata);
$string{$i} = $hack;
}
}
function yourFunc($value, $position) {
echo $value . ' ';
}
function yourOtherFunc(&$value, $position) {
$value = str_rot13($value);
}
# NOTE: We now need this ugly $x = hack.
string_walk($x = 'interesting', 'yourFunc');
// Ouput: i n t e r e s t i n g
string_walk($x = 'interesting', 'yourOtherFunc');
echo $x;
// Output: vagrerfgvat
?>
Also note that calling str_rot13() directly on $x would be much faster ;-) just a sample.
chaley at brtransport dot com ¶
10 years ago
There is a note about 3 years ago regarding using this for trimming. array_map() may be cleaner for this. I haven't checked the time/resource impact:
$result = array_map("trim", $array);
Maxim ¶
13 years ago
Note that using array_walk with intval is inappropriate.
There are many examples on internet that suggest to use following code to safely escape $_POST arrays of integers:
<?php
array_walk($_POST['something'],'intval'); // does nothing in PHP 5.3.3
?>
It works in _some_ older PHP versions (5.2), but is against specifications. Since intval() does not modify it's arguments, but returns modified result, the code above has no effect on the array and will leave security hole in your website.
You can use following instead:
<?php
$_POST['something'] = array_map(intval,$_POST['something']);
?>
rustamabd at gmail dot com ¶
14 years ago
Don't forget about the array_map() function, it may be easier to use!
Here's how to lower-case all elements in an array:
<?php
$arr = array_map('strtolower', $arr);
?>
EllisGL ¶
6 years ago
For those that think they can't use array_walk to change / replace a key name, here you go:
<?php
function array_explore(array &$array, callable $callback)
{
array_walk($array, function(&$value, $key) use (&$array, $callback)
{
$callback($array, $key, $value);
if(is_array($value))
{
array_explore($value, $callback);
}
});
}
/**
* Stolen from: https://stackoverflow.com/questions/13233405/change-key-in-associative-array-in-php
*/
function renameKey(array &$data, $oldKey, $newKey, $ignoreMissing = false, $replaceExisting = false)
{
if (!empty($data))
{
if (!array_key_exists($oldKey, $data))
{
if ($ignoreMissing)
{
return FALSE;
}
throw new \Exception('Old key does not exist.');
}
else
{
if (array_key_exists($newKey, $data))
{
if ($replaceExisting)
{
unset($data[$newKey]);
}
else
{
throw new \Exception('New key already exist.');
}
}
$keys = array_keys($data);
// Fix from EllisGL: http://php.net/manual/en/function.array-search.php#122377
$keys[array_search($oldKey, array_map('strval', $keys))] = $newKey;
$data = array_combine($keys, $data);
return TRUE;
}
}
return FALSE;
}
$array = [
"_10fish" => 'xyz',
"_11fish" => [
"_22" => "a", "b", "c"
],
"someFish" => [
'xyz',
'@attributes' => ['type' => 'cod']
]
];
array_explore($array, function(&$value, $key)
{
// Replace key '@attrutes' with '_attributes'
if('@attributes' === $key)
{
renameKey($value, $key, '_attributes');
}
});
print_r($array);
?>
erelsgl at gmail dot com ¶
15 years ago
If you want to unset elements from the callback function, maybe what you really need is array_filter.
Andrzej Martynowicz at gmail dot com ¶
19 years ago
It can be very useful to pass the third (optional) parameter by reference while modifying it permanently in callback function. This will cause passing modified parameter to next iteration of array_walk(). The exaple below enumerates items in the array:
<?php
function enumerate( &$item1, $key, &$startNum ) {
$item1 = $startNum++ ." $item1";
}
$num = 1;
$fruits = array( "lemon", "orange", "banana", "apple");
array_walk($fruits, 'enumerate', $num );
print_r( $fruits );
echo '$num is: '. $num ."\n";
?>
This outputs:
Array
(
[0] => 1 lemon
[1] => 2 orange
[2] => 3 banana
[3] => 4 apple
)
$num is: 1
Notice at the last line of output that outside of array_walk() the $num parameter has initial value of 1. This is because array_walk() does not take the third parameter by reference.. so what if we pass the reference as the optional parameter..
<?php
$num = 1;
$fruits = array( "lemon", "orange", "banana", "apple");
array_walk($fruits, 'enumerate', &$num ); // reference here
print_r( $fruits );
echo '$num is: '. $num ."\n";
echo "we've got ". ($num - 1) ." fruits in the basket!";
?>
This outputs:
Array
(
[0] => 1 lemon
[1] => 2 orange
[2] => 3 banana
[3] => 4 apple
)
$num is: 5
we've got 4 fruits in the basket!
Now $num has changed so we are able to count the items (without calling count() unnecessarily).
As a conclusion, using references with array_walk() can be powerful toy but this should be done carefully since modifying third parameter outside the array_walk() is not always what we want.
taj at yahoo dot fr ¶
5 years ago
// We can make that with this simple FOREACH loop :
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
foreach($fruits as $cls => $vls)
{
$fruits[$cls] = "fruit: ".$vls;
}
Results:
Array
(
[d] => fruit: lemon
[a] => fruit: orange
[b] => fruit: banana
[c] => fruit: apple
)
fantomx1 at gmail dot com ¶
8 years ago
Since array_walk cannot modify / change / reindex keys as already mentioned, i provide this small wrapping function which accomplishes passing array reference and index using closures , "use" keyword.
function indexArrayByElement($array, $element)
{
$arrayReindexed = [];
array_walk(
$array,
function ($item, $key) use (&$arrayReindexed, $element) {
$arrayReindexed[$item[$element]] = $item;
}
);
return $arrayReindexed;
}
alex_stanhope at hotmail dot com ¶
13 years ago
I wanted to walk an array and reverse map it into a second array. I decided to use array_walk because it should be faster than a reset,next loop or foreach(x as &$y) loop.
<?php
$output = array();
array_walk($input, 'gmapmark_reverse', $output);
function gmapmark_reverse(&$item, $index, &$target) {
$target[$item['form_key']] = $index;
}
?>
In my debugger I can see that $target is progressively updated, but when array_walk returns, $output is empty. If however I use a (deprecated) call-by-reference:
<?php
array_walk($input, 'gmapmark_reverse', &$output);
?>
$output is returned correctly. Unfortunately there's not an easy way to suppress the warnings:
<?php
@array_walk($input, 'gmapmark_reverse', &$output);
?>
doesn't silence them. I've designed a workaround using a static array:
<?php
$reverse = array();
array_walk($input, 'gmapmark_reverse');
// call function one last time to get target array out, because parameters don't work
$reverse = gmapmark_reverse($reverse);
function gmapmark_reverse(&$item, $index = 0) {
static $target;
if (!$target) {
$target = array();
}
if (isset($item['form_key'])) {
$target[$item['form_key']] = $index;
}
return($target);
}
?>
brian at access9 dot net ¶
11 years ago
array_walk does not work on SplFixedArray objects:
<?php
$array = new SplFixedArray(2);
$array[0] = 'test_1';
$array[1] = 'test_2';
array_walk($array, function(&$val){
$val .= '__';
return $val;
});
foreach ($array as $a) {
echo "$a\n";
}
?>
result is:
test_1
test_2
zlobnygrif at gmail dot com ¶
11 years ago
Some speed tests
<?php
// Test results
$array1 = test('array_walk');
$array2 = test('array_walk_list_each');
$array3 = test('array_walk_foreach1');
$array4 = test('array_walk_foreach2');
// Check arrays for equal
var_dump($array1 == $array2, $array1 == $array3, $array1 == $array4);
// Test function 1
function array_walk_list_each(&$array, $function, $userData = null) {
while ( list($key, $value) = each($array) )
$function($array[$key], $key, $userData);
}
// Test function 2
function array_walk_foreach1(&$array, $function, $userData = null) {
foreach ($array as $key => &$value )
$function($value, $key, $userData);
}
// Test function 3
function array_walk_foreach2(&$array, $function, $userData = null) {
foreach ($array as $key => $value )
$function($array[$key], $key, $userData);
}
function some_function(&$value, $key, $userData) {
$value = "$key => $userData";
}
function test($function, $count = 10000, $arrayElements = 1000) {
echo $function, ' ... ';
$array = array_fill(0, $arrayElements, "some text value");
$timer = microtime(true);
for( $i = 0; ++$i < $count; )
$function($array, 'some_function', 'some user data');
printf("%.3f sec\n", microtime(true) - $timer);
return $array;
}
?>
Output (PHP 5.4.9-4ubuntu2.2 (cli) (built: Jul 15 2013 18:24:39))
=========================
array_walk ... 13.572 sec
array_walk_list_each ... 0.027 sec
array_walk_foreach1 ... 15.356 sec
array_walk_foreach2 ... 17.416 sec
bool(true)
bool(true)
bool(true)
Output (PHP 5.5.0 (cli) (built: Jul 16 2013 17:59:42) - same server)
=========================
array_walk ... 4.776 sec
array_walk_list_each ... 0.006 sec
array_walk_foreach1 ... 4.482 sec
array_walk_foreach2 ... 5.166 sec
bool(true)
bool(true)
bool(true)
PHP 5.5 array_walk looks pretty good but list each is more and more quickly...
matthew at codenaked dot org ¶
14 years ago
Using lambdas you can create a handy zip function to zip together the keys and values of an array. I extended it to allow you to pass in the "glue" string as the optional userdata parameter. The following example is used to zip an array of email headers:
<?php
/**
* Zip together the keys and values of an array using the provided glue
*
* The values of the array are replaced with the new computed value
*
* @param array $data
* @param string $glue
*/
function zip(&$data, $glue=': ')
{
if(!is_array($data)) {
throw new InvalidArgumentException('First parameter must be an array');
}
array_walk($data, function(&$value, $key, $joinUsing) {
$value = $key . $joinUsing . $value;
}, $glue);
}
$myName = 'Matthew Purdon';
$myEmail = 'matthew@example.com';
$from = "$myName <$myEmail>";
$headers['From'] = $from;
$headers['Reply-To'] = $from;
$headers['Return-path'] = "<$myEmail>";
$headers['X-Mailer'] = "PHP" . phpversion() . "";
$headers['Content-Type'] = 'text/plain; charset="UTF-8"';
zip($headers);
$headers = implode("\n", $headers);
$headers .= "\n";
echo $headers;
/*
From: Matthew Purdon <matthew@example.com>
Reply-To: Matthew Purdon <matthew@example.com>
Return-path: <matthew@example.com>
X-Mailer: PHP5.3.2
Content-Type: text/plain; charset="UTF-8"
*/
?>
op_adept at yahoo dot co dot uk ¶
13 years ago
Prefix array values with keys and retrieve as a glued string, the original array remains unchanged. I used this to create some SQL queries from arrays.
<?php
function array_implode_prefix($outer_glue, $arr, $inner_glue, $prefix=false){
array_walk( $arr , "prefix", array($inner_glue, $prefix) );
return implode($outer_glue, $arr);
}
function prefix(&$value, $key, array $additional){
$inner_glue = $additional[0];
$prefix = isset($additional[1])? $additional[1] : false;
if($prefix === false) $prefix = $key;
$value = $prefix.$inner_glue.$value;
}
//Example 1:
$order_by = array("3"=>"ASC", "2"=>"DESC", "7"=>"ASC");
echo array_implode_prefix(",", $order_by, " ");
//Output: 3 ASC,2 DESC,7 ASC
//Example 2:
$columns = array("product_id", "category_id", "name", "description");
$table = "product";
echo array_implode_prefix(", ", $columns, ".", $table);
//Output:product.product_id, product.category_id, product.name, product.description
//Example 3 (function prefix) won't really be used on its own
$pre= "vacation";
$value = "lalaland";
prefix($value, $pre, array("."));
echo $value;
//Output: vacation.lalaland
?>
jab_creations_-at_-yahoo_-dot-_com ¶
15 years ago
Unfortunately I spent a lot of time trying to permanently apply the effects of a function to an array using the array_walk function when instead array_map was what I wanted. Here is a very simple though effective example for those who may be getting overly frustrated with this function...
<?php
$fruits = array("Lemony & Fresh","Orange Twist","Apple Juice");
print_r($fruits);
echo '<br />';
function name_base($key)
{
$name2 = str_replace(" ", "_", $key);
$name3 = str_replace("&", "and", $name2);
$name4 = strtolower($name3);
echo $name4.'<br />';
return $name4;
}
echo '<br />';
$test = array_map('name_base', $fruits);
$fruits_fixed = $test;
echo '<br />';
print_r($fruits_fixed);
?>
http://alex.moutonking.com/wordpress ¶
13 years ago
For completeness one has to mention the possibility of using this function with PHP 5.3 closures:
<?php
$names = array("D\'Artagnan", "Aramis", "Portos");
array_walk($names, function(&$n) {
$n = stripslashes($n);
});
?>
The trap with array_walk being it doesn't return the array, instead it's modified by reference.
arekandrei at yandex dot ru ¶
14 years ago
You can use lambda function as a second parameter:
<?php
array_walk($myArray, function(&$value, $key){
// if you want to change array values then "&" before the $value is mandatory.
});
?>
Example (multiply positive values by two):
<?php
$myArray = array(1, 2, 3, 4, 5);
array_walk($myArray, function(&$value, $index){
if ($value > 0) $value *= 2;
});
?>
manuscle at gmail dot com ¶
12 years ago
example with closures, checking and deleting value in array:
<?php
$array = array('foo' => 'bar', 'baz' => 'bat');
array_walk($array, function($val,$key) use(&$array){
if ($val == 'bar') {
unset($array[$key]);
}
});
var_dump($array);
@jfredys ¶
13 years ago
I was looking for trimming all the elements in an array, I found this as the simplest solution:
<?php
array_walk($ids, create_function('&$val', '$val = trim($val);'));
?>
diyism ¶
16 years ago
When i pass the third parameter by reference in php5.2.5,
happened this: Warning: Call-time pass-by-reference has been deprecated - argument passed by value...
And to set allow_call_time_pass_reference to true in php.ini won't work, according to http://bugs.php.net/bug.php?id=19699 thus to work around:
<?php
array_walk($arrChnOut, create_function('&$v, $k, $arr_rtn', 'if ($k{0}!="_") {$arr_rtn[0]["_".$v[\'ID\']]=$v; unset($arr_rtn[0][$k]);}'), array(&$arrChnOut));
?>
theking2(at)king.ma ¶
10 months ago
This function can be used to add the values in one array to another:
<?php
echo '<pre>';
// example code
$a = [ 1, 2, 3, 4, 5, 6];
$c = [10,20,30,40,50,60];
array_walk($a,
function(&$item, $key, $y) { $item += $y[$key];},
$c
);
print_r($a);
// result
Array
(
[0] => 11
[1] => 22
[2] => 33
[3] => 44
[4] => 55
[5] => 66
)
christopher at crmldnrs dot com ¶
2 years ago
public function big_endian_array_walk(array $array, $callback) {
end($array);
for($i=sizeof($array);$i>0;$i--) {
$key = key($array);
$value = array_pop($array);
if(preg_match('/^[a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*$/', $value)) {
call_user_func_array($callback, [$value, $key]);
}
}
}
christopher at crmldnrs dot com ¶
2 years ago
public function big_endian_array_walk(array $array, $callback) {
end($array);
for($i=sizeof($array);$i>0;$i--) {
$key = key($array);
$value = array_pop($array);
if(preg_match('/^[a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*$/', $value)) {
call_user_func_array($callback, [$value, $key]);
}
}
}
I just wanted to walk from the end to the beginning.
vrrivaro at YESIUSEGMAIL dot gmail dot SO dot com ¶
7 years ago
The output of the example is only correct if viewed through a web browser. If you pass it through to PHP-CLI, you will get to see the additional HTML line breaks, however.
emre ¶
3 years ago
You can change the key or value with array_walk if you use the temporal returned array in global inside the function. For example:
$array = ['a'=>10, 'b'=>20];
$sequence = array ();
$newArray = array_values(array_walk($array, 'fn'));
function fn(&$val,$key){
global $sequence;
$sequence [] = $val;
}
No need to concern about the place of the internal pointer for the baby array. You have now rewinded, 0 based new array, string key one instead.
mystral77 at gmail dot com ¶
4 years ago
Hello,
If you want to add values with same key from two arrays :
<?php
function add(&$item,$key,$search) {
$item += (is_array($search))?((isset($search[$key]))?$search[$key]:0):0;
}
$a = ["orange" => 2, "banana" => 3, "apple" => 1];
$b = ["orange" => 1, "apple" => 4];
array_walk($c,"add",$b);
echo "<pre>".print_r($c,true)."</pre>";
?>
This will output:
"orange" => 3,
"banana" => 3,
"apple" => 5
espertalhao04 at hotmail dot com ¶
11 years ago
here is a simple and yet easy to use implementation of this function.
the 'original' function has the problem that you can't unset a value.
with my function, YOU CAN!
<?php
function array_walk_protected(&$a,$s,$p=null)
{
if(!function_exists($s)||!is_array($a))
{
return false;
}
foreach($a as $k=>$v)
{
if(call_user_func_array($s,array(&$a[$k],$k,$p))===false)
{
unset($a[$k]);
}
}
}
function get_name(&$e,$i,$p)
{
echo "$i: $e<br>";
return false;
}
$m=array('d'=>'33','Y'=>55);
array_walk_protected($m,'get_name');
var_dump($m); //returns array(0) { }
?>
i called it array_walk_protected because it is protected against the unexpected behavior of unsetting the value with the original function.
to delete an element, simply return false!!!
nothing else is needed!
unsetting $e, under your created function, will keep the same array as-is, with no changes!
by the way, the function returns false if $a is not array or $s is not a string!
limitations: it only can run user defined functions.
i hope you like it!
gold[at]evolved.net.nz ¶
11 years ago
For all those people trying to shoe-horn trim() into array_walk() and have found all these tricks to work around the issue with array_walk() passing 2 parameters to the callback...
Check out array_map().
http://php.net/array_map
It's all sorts of win.
For the record. I'm one of these people and after 15 years of php development I'm pleased to say that there's still things I'm learning. :) I just found out about array_map() myself...
el_porno at web dot de ¶
19 years ago
You want to get rid of the whitespaces users add in your form fields...?
Simply use...:
class SomeVeryImportantClass
{
...
public function mungeFormData(&$data)
{
array_walk($data, array($this, 'munge'));
}
private function munge(&$value, &$key)
{
if(is_array($value))
{
$this->mungeFormData($value);
}
else
{
$value = trim($value);
}
}
...
}
so...
$obj = new SomeVeryImportantClass;
$obj->mungeFormData($_POST);
___
eNc
jerk at yoosic dot de ¶
17 years ago
if you want to modify every value of an multidimensional array use this function used here:
<?php
$array = array (1=>1, 2=> 2, 3 => array(1=>11, 2=>12, 3=>13));
$text = "test";
function modarr(&$array, $text) {
foreach ($array as $key => $arr) {
if(is_array($arr)) $res[$key] = modarr(&$arr,$text);
// modification function here
else $res[$key] = $arr.$text;
}
return $res;
}
$erg = modarr($array, $text);
print_r($erg);
?>
result will be_
<?php
Array ( [1] => 1test [2] => 2test [3] => Array ( [1] => 11test [2] => 12test [3] => 13test ) )
?>
peterzuzek AT gmail DOT com ¶
15 years ago
I had some problems using this function - it didn't want to apply PHP-defined functions. So I decided to write my own - here it is. I had to use some generic-programming skills, didn't really checked the speed (I think it could be slow)... I believe it could be much better, but I don't know, how - well, I guess multiple array support and recursion would be nice. So?
Prototype:
bool arrayWalk(array &$arry, callback $callback, mixed $params=false)
<?php
function arrayWalk(&$arry, $callback, $params=false) {
$P=array(""); // parameters
$a=""; // arguement string :)
if($params !== false) { // add parameters
if(is_array($params)) { // multiple additional parameters
foreach($params as $par)
{ $P[]=$par; }
}
else // just one additional
{ $P[]=$params; }
}
for( // create the arguement string
$i=0; isset($P[$i]); ++$i
)
{ $a.='$'.chr($i + 97).', '; } // random argument names
$a=substr($a, 0, -2); // to get rid of the last comma and two spaces
$func=create_function($a, 'return '.$callback.'('.$a.');'); // the generic function
if(is_callable($func)) {
for( // cycle through array
$i=0; isset($arry[$i]); ++$i
) {
$P[0]=$arry[$i]; // first element must be the first argument - array value
$arry[$i] = call_user_func_array($func, $P); // assign the new value obtained by the generic function
}
}
else
{ return false; } // failure - function not callable
return true; // success!
} // arrayWalk()
?>
One big problem I've noticed so far - for example, if you wanted to use str_replace on the array, you'd fail - simply because of the arguement order of str_replace, where the string modified is the third arguement, not the first as arrayWalk requires.
So, still some work left...
Enlightened One ¶
19 years ago
Beware that "array ($this, method)" construct. If you're wanting to alter members of the "$this" object inside "method" you should construct the callback like this:
$callback[] = &$this;
$callback[] = method;
array_walk ($input, $callback);
Creating your callback using the array() method as suggested by "appletalk" results in a copy of $this being passed to method, not the original object, therefor any changes made to the object by method will be lost when array_walk() returns. While you could construct the callback with "array(&$this, method)", I believe this relies on the deprecated runtime pass-by-reference mechanism which may be removed in future releases of PHP. Better to not create a dependence on that feature now than having to track it down and fix it in the future.
tufanbarisyildirim at gmail dot com ¶
13 years ago
Filter an array by using key.
<?php
$product_1 = 'test';
$product_2 = 'test 2';
function array_key_filter($array,$callback = 'trim')
{
$filtered = array();
array_walk($array,function ($degeri,$degisken_adi) use (&$filtered,$callback)
{
if($callback($degisken_adi))
{
$filtered[$degisken_adi] = $degeri;
}
});
return $filtered;
}
#using
$degiskenler = array_key_filter(get_defined_vars(),function($key)
{
return strpos($key,'product_') === 0;
});
print_r($degiskenler);
?>
output:
Array
(
[product_1] => test
[product_2] => test 2
)
