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array_intersect_key

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

array_intersect_keyCalcula a interseção de arrays, comparando pelas chaves

Descrição

array_intersect_key(array $array, array ...$arrays): array

array_intersect_key() retorna um array contendo todos os valores de array que tem as mesmas chaves presentes em todos os argumentos.

Parâmetros

array

O array com as chaves a serem verificadas.

arrays

Arrays para comparar as chaves.

Valor Retornado

Retorna um array associativo contendo todos os valores de array que estão presentes em todos os argumentos.

Registro de Alterações

Versão Descrição
8.0.0 Esta função agora pode ser chamada com apenas um parâmetro. Anteriormente, pelo menos dois parâmetros eram necessários.

Exemplos

Exemplo #1 Exemplo da array_intersect_key()

<?php
$array1
= array('azul' => 1, 'vermelho' => 2, 'verde' => 3, 'roxo' => 4);
$array2 = array('verde' => 5, 'azul' => 6, 'amarelo' => 7, 'ciano' => 8);

var_dump(array_intersect_key($array1, $array2));
?>

O exemplo acima produzirá:

array(2) {
  ["azul"]=>
  int(1)
  ["verde"]=>
  int(3)
}

Em nosso exemplo você pode ver que somente as chaves 'azul' e 'verde' estão presentes em ambos os array e assim são retornados. Também note que os valores das chaves 'azul' e 'verde' diferem nos dois arrays. A combinação ocorre porque somente as chaves são verificadas. Os valores retornados são do array.

As duas chaves do par key => value são considerados iguais somente se (string) $key1 === (string) $key2 . Em outras palavras um verificação do tipo é executada, então a representação string precisa ser a mesma.

Veja Também

  • array_diff() - Computa as diferenças entre arrays
  • array_udiff() - Computa a diferença de arrays usando uma função de callback para comparação dos dados
  • array_diff_assoc() - Computa a diferença entre arrays com checagem adicional de índice
  • array_diff_uassoc() - Computa a diferença entre arrays com checagem adicional de índice que feita por uma função de callback fornecida pelo usuário
  • array_udiff_assoc() - Computa a diferença entre arrays com checagem adicional de índice, compara dados por uma função de callback
  • array_udiff_uassoc() - Computa a diferença entre arrays com checagem adicional de índice, compara dados e índices por uma função de callback
  • array_diff_key() - Computa a diferença entre arrays usando as chaves na comparação
  • array_diff_ukey() - Computa a diferença entre arrays usando uma função callback na comparação de chaves
  • array_intersect() - Calcula a interseção entre arrays
  • array_intersect_assoc() - Computa a interseção de arrays com uma adicional verificação de índice
  • array_intersect_uassoc() - Computa a interseção de arrays com checagem de índice adicional, compara índices por uma função de callback
  • array_intersect_ukey() - Computa a interseção de arrays usando uma função de callback nas chaves para comparação

add a note

User Contributed Notes 11 notes

up
265
vladas dot dirzys at gmail dot com
11 years ago
Simple key white-list filter:

<?php
$arr
= array('a' => 123, 'b' => 213, 'c' => 321);
$allowed = array('b', 'c');

print_r(array_intersect_key($arr, array_flip($allowed)));
?>

Will return:
Array
(
[b] => 213
[c] => 321
)
up
10
Anonymous
2 years ago
Note that the order of the keys in the returned array is the same as the order of the keys in the source array.

To sort by the second array, then you may do so through array_replace.

<?php
$array
= array(
'two' => 'a',
'three' => 'b',
'one' => 'c',
);

$keyswant = array(
'one' => '',
'three' => '',
);

print_r(array_intersect_key(array_replace($keyswant, $array), $keyswant));

?>

Shows:

Array
(
[one] => c
[three] => b
)

Rather than:

Array
(
[three] => b
[one] => c
)
up
22
github.com/xmarcos
9 years ago
[Editor's note: changed array_merge_recursive() to array_replace_recursive() to fix the script]

Here is a better way to merge settings using some defaults as a whitelist.

<?php

$defaults
= [
'id' => 123456,
'client_id' => null,
'client_secret' => null,
'options' => [
'trusted' => false,
'active' => false
]
];

$options = [
'client_id' => 789,
'client_secret' => '5ebe2294ecd0e0f08eab7690d2a6ee69',
'client_password' => '5f4dcc3b5aa765d61d8327deb882cf99', // ignored
'client_name' => 'IGNORED', // ignored
'options' => [
'active' => true
]
];

var_dump(
array_replace_recursive($defaults,
array_intersect_key(
$options, $defaults
)
)
);

?>

Output:

array (size=4)
'id' => int 123456
'client_id' => int 789
'client_secret' => string '5ebe2294ecd0e0f08eab7690d2a6ee69' (length=32)
'options' =>
array (size=2)
'trusted' => boolean false
'active' => boolean true
up
5
Reed Silver
9 years ago
If you want an array that has no key value pairs added from the second array:

$new = array_intersect_key($b, $a) + $a;
up
11
pgl at yoyo dot org
12 years ago
Note that the order of the keys in the returned array is the same as the order of the keys in the source array. eg:

<?php
$array
= array(
'two' => 'a',
'three' => 'b',
'one' => 'c',
);

$keyswant = array(
'one' => '',
'three' => '',
);

print_r(array_intersect_key($array, $keyswant));

?>

Shows:

Array
(
[three] => b
[one] => c
)
up
6
CBWhiz at gmail dot com
16 years ago
I have found the following helpful:
<?PHP
function array_merge_default($default, $data) {
$intersect = array_intersect_key($data, $default); //Get data for which a default exists
$diff = array_diff_key($default, $data); //Get defaults which are not present in data
return $diff + $intersect; //Arrays have different keys, return the union of the two
}
?>
It's use is like both of the functions it uses, but keeps defaults and _only_ defaults. It's designed for key arrays, and i'm not sure how it will work on numeric indexed arrays.

Example:
<?PHP
$default
= array(
"one" => 1,
"two" => 2
);
$untrusted = array(
"one" => 42,
"three" => 3
);
var_dump(array_merge_default($default, $untrusted));

array(
2) {
[
"two"]=>
int(2)
[
"one"]=>
int(42)
}

?>
up
1
chrisbloom7 at gmail dot com
14 years ago
Regarding php at keithtylerdotcom solution to emulate

<?php
$z
= someFuncReturningAnArray()['some_key'];
?>

His recommended solution will still return an array. To get the value of a single key in an array returned by a function, simply add implode() to the recipe:

<?php
function someFuncReturningAnArray() {
return array(
'a' => 'b',
'c' => 'd',
'e' => 'f',
'g' => 'h',
'i' => 'j'
);
}

//traditional way
$temp = someFuncReturningAnArray();
$b = $temp['a'];
echo
print_r($b, 1) . "\n----------\n";

//keithtylerdotcom one-line method
$b = array_intersect_key(someFuncReturningAnArray(), array('a'=>''));
echo
print_r($b, 1) . "\n----------\n";

//better one line method
$b = implode('', array_intersect_key(someFuncReturningAnArray(), array('a'=>'')));
echo
print_r($b, 1) . "\n----------\n";
?>
up
2
Anton Backer
17 years ago
Jesse: no, array_intersect_key does not accomplish the same thing as what you posted:

array_flip (array_intersect (array_flip ($a), array_flip ($b)))

because when the array is flipped, values become keys. having duplicate values is not a problem, but having duplicate keys is. array_flip resolves it by keeping only one of the duplicates and discarding the rest. by the time you start intersecting, you've already lost information.
up
0
markus dot kappe at dix dot at
14 years ago
<?php
/**
* calculates intersection of two arrays like array_intersect_key but recursive
*
* @param array/mixed master array
* @param array array that has the keys which should be kept in the master array
* @return array/mixed cleand master array
*/
function myIntersect($master, $mask) {
if (!
is_array($master)) { return $master; }
foreach (
$master as $k=>$v) {
if (!isset(
$mask[$k])) { unset ($master[$k]); continue; } // remove value from $master if the key is not present in $mask
if (is_array($mask[$k])) { $master[$k] = $this->myIntersect($master[$k], $mask[$k]); } // recurse when mask is an array
// else simply keep value
}
return
$master;
}
?>
up
-1
pixelf3hler at visualize-me dot de
10 years ago
in case you came here looking for a function that returns an array containing the values of `all` arrays with intersecting keys:
<?php
function array_merge_on_key($key, $array1, $array2) {
$arrays = array_slice(func_get_args(), 1);
$r = array();
foreach(
$arrays as &$a) {
if(
array_key_exists($key, $a)) {
$r[] = $a[$key];
continue;
}
}
return
$r;
}
// example:
$array1 = array("id" => 12, "name" => "Karl");
$array2 = array("id" => 4, "name" => "Franz");
$array3 = array("id" => 9, "name" => "Helmut");
$array4 = array("id" => 10, "name" => "Kurt");

$result = array_merge_on_key("id", $array1, $array2, $array3, $array4);

echo
implode(",", $result); // => 12,4,9,10
?>
up
-3
pdemaziere at gmail dot com
15 years ago
Just a simple script if you want to use one array, which contains only zeros and ones, as mask for another one (both arrays must have the same size of course). $outcome is an array that contains only those values from $source where $mask is equal to 1.

<?php
$outcome
= array_values(array_intersect_key( array_values($source), array_filter(array_values($mask)) ));
?>

PS: the array_values() function is necessary to ensure that both arrays have the same numbering/keys, otherwise your masking does not behave as you expect.

Enjoy!
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