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
)
PHP - Manual: array_intersect_key
2024-12-22
array_intersect_key
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
array_intersect_key — 使用键名比较计算数组的交集
说明
array_intersect_key(array
$array, array ...$arrays): array
array_intersect_key() 返回一个数组，该数组包含了所有出现在
array 和其它参数数组中同时存在的键名的值。
参数
-
array -
要检查的数组，作为主值。
-
arrays -
要被对比的数组。
返回值
返回一个关联数组，该数组包含了所有出现在
array 和其它参数数组中同时存在的键名的值。
范例
示例 #1 array_intersect_key() 例子
<?php
$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8);
var_dump(array_intersect_key($array1, $array2));
?>
以上例程会输出：
array(2) {
["blue"]=>
int(1)
["green"]=>
int(3)
}
上例中可以看到，只有 'blue'
和 'green' 两个键名同时出现在两个数组中，因此被返回。另外注意
'blue' 和 'green'
的值在两个数组中是不同的。但因为只检查键名，因此还是匹配。返回的只是
array 中的值。
在 key => value 对中的两个键名仅在
(string) $key1 === (string) $key2
时才被认为相等。换句话说，执行了严格的类型检查，因此字符串的表达形式必须相同。
参见
- array_diff() - 计算数组的差集
- array_udiff() - 用回调函数比较数据来计算数组的差集
- array_diff_assoc() - 带索引检查计算数组的差集
- array_diff_uassoc() - 用用户提供的回调函数做索引检查来计算数组的差集
- array_udiff_assoc() - 带索引检查计算数组的差集，用回调函数比较数据
- array_udiff_uassoc() - 带索引检查计算数组的差集，用回调函数比较数据和索引
- array_diff_key() - 使用键名比较计算数组的差集
- array_diff_ukey() - 用回调函数对键名比较计算数组的差集
- array_intersect() - 计算数组的交集
- array_intersect_assoc() - 带索引检查计算数组的交集
- array_intersect_uassoc() - 带索引检查计算数组的交集，用回调函数比较索引
- array_intersect_ukey() - 在键名上使用回调函数来比较计算数组的交集
add a note
User Contributed Notes 11 notes
vladas dot dirzys at gmail dot com ¶
9 years ago
Anonymous ¶
10 months 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
)
github.com/xmarcos ¶
8 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
Reed Silver ¶
7 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;
pgl at yoyo dot org ¶
10 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
)
chrisbloom7 at gmail dot com ¶
12 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";
?>
CBWhiz at gmail dot com ¶
14 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, $untrusted));
array(2) {
["two"]=>
int(2)
["one"]=>
int(42)
}
?>
Anton Backer ¶
16 years ago
Jesse: no, array_intersect_key does not accomplish the same thing as what you posted:
array_flip (array_intersect (array_flip ($a), array_flip ($b)))
because when the array is flipped, values become keys. having duplicate values is not a problem, but having duplicate keys is. array_flip resolves it by keeping only one of the duplicates and discarding the rest. by the time you start intersecting, you've already lost information.
markus dot kappe at dix dot at ¶
12 years ago
<?php
/**
* calculates intersection of two arrays like array_intersect_key but recursive
*
* @param array/mixed master array
* @param array array that has the keys which should be kept in the master array
* @return array/mixed cleand master array
*/
function myIntersect($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 $master;
}
?>
pixelf3hler at visualize-me dot de ¶
8 years ago
in case you came here looking for a function that returns an array containing the values of `all` arrays with intersecting keys:
<?php
function array_merge_on_key($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
?>
pdemaziere at gmail dot com ¶
13 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!
官方地址：https://www.php.net/manual/en/function.array-intersect-key.php
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