One of the ways to get intersection of two arrays is as follows:
<?php
function arrayIntersect( $primary_array, $secondary_array ) {
if ( !is_array( $primary_array ) || !is_array( $secondary_array ) ) {
return false;
}
if ( !empty( $primary_array ) ) {
foreach( $primary_array as $key => $value ) {
if ( !isset( $secondary_array[$key] ) ) {
unset( $primary_array[$key] );
} else {
if ( serialize( $secondary_array[$key] ) != serialize( $value ) ) {
unset( $primary_array[$key] );
}
}
}
return $primary_array;
} else {
return array();
}
}
?>
It would pay attention to both keys and values even if values would be arrays as well. One important note is that if value of $primary_array is yet another array, its order of key & value pairs becomes important for matching.
array_intersect_assoc
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
array_intersect_assoc — 带索引检查计算数组的交集
说明
array_intersect_assoc() 返回一个数组，该数组包含了所有在
array 和其它参数数组中同时存在的值。注意和
array_intersect() 不同的是，键名也用于比较。
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，该数组包含了所有在
array 和其它参数数组中同时存在的值。
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | 现在可以仅使用一个参数调用此函数。以前，至少需要两个参数。 |
示例
示例 #1 array_intersect_assoc() 例子
<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "b" => "yellow", "blue", "red");
$result_array = array_intersect_assoc($array1, $array2);
print_r($result_array);
?>以上示例会输出：
Array
(
[a] => green
)
上面例子中可以看到，只有键值对 "a" =>
"green" 在两个数组中都存在，从而被返回。
值 "red" 没有被返回，是因为在
$array1 中它的键名是 0
而在 $array2 中 "red" 的键名是
1，键 "b" 没有返回的原因是，它的值和其他数组不同。
仅在 (string) $elem1 === (string) $elem2 时，
key => value 才被认为是相等的。
也就是说使用了严格的类型检查，字符串的表达形式必须相同。
参见
- array_intersect() - 计算数组的交集
- array_uintersect_assoc() - 带索引检查计算数组的交集，用回调函数比较数据
- 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_uintersect_uassoc() - 带索引检查计算数组的交集，用单独的回调函数比较数据和索引
- array_diff() - 计算数组的差集
- array_diff_assoc() - 带索引检查计算数组的差集
add a note
User Contributed Notes 4 notes
Whitend ¶
12 years ago
vandor at progressive dot hu ¶
19 years ago
# ket tomb kulcs alapu metszetet szamitja ki, az erteken is ellenorzest vegez
#
# calculating (key base) intersection of arrays (value are checked)
# use: $result_array = array_intersect_assoc($a1, $a2, $a3,..);
#
##
# original code by [jochem at iamjochem dawt com] : array_diff_keys()
<?php
function array_intersect_assoc() {
$args = func_get_args();
$res = $args[0];
for ($i=1;$i<count($args);$i++) {
if (!is_array($args[$i])) {continue;}
foreach ($res as $key => $data) {
if ( (!array_key_exists($key, $args[$i])) || ( (isset($args[$i][$key])) && ($args[$i][$key] !== $res[$key]) ) ) {
unset($res[$key]);
}
}
}
return $res;
}
?>
<?php
$array1 = array("a"=>"green", "b"=>"brown", "c"=>"blue", "red");
$array2 = array("a"=>"green", "b"=>"yellow", "c"=>"yellow", "red");
$a = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow');
$b = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow', 'e'=>'yellow');
$result_array = array_intersect_assoc($a, $b, $array1, $array2);
?>
$args array will look like:
(
0 =>
(
a => green
b => brown
c => yellow
)
1 =>
(
a => green
b => brown
c => yellow
e => yellow
)
2 =>
(
a => green
b => brown
c => blue
0 => red
)
3 =>
(
a => green
b => yellow
c => yellow
0 => red
)
)
$result_array will look like:
(
a => green
)
StR: str at strgt dot cjb dot net ¶
19 years ago
To find the keys that are in 2 arrays, without caring of the values:
This is a function i needed, and it also returns the values of the first array
<?php
function array_key_intersect(&$a, &$b) {
$array = array();
while (list($key,$value) = each($a)) {
if (isset($b[$key]))
$array[$key] = $value;
}
return $array;
}
?>
Jim Yaghi ¶
7 years ago
Remember, null values will be interpreted as, "key does not exist." eg,
$a = ['apples' => 1, 'oranges' => 2, 'turtles' => null, 'bananas'=>4];
$b = ['apples'=>10, 'turtles' => 11, 'eggs'=>12];
$c = array_intersect_assoc($b,$a);
You might have expected $c to contain:
['oranges' => 10, 'turtles' => 11]
In fact, 'turtles' has a null value in the $a array, therefore the $c array contains only:
['oranges' => 10]
Something to keep in mind if using array_intersect_assoc to filter valid entries, eg in a mySQL insertion pre-processing or nerdy API that doesn't like extra params.
