array_intersect_assoc()

(PHP 4 >= 4.3.0, PHP 5, PHP 7)

带索引检查计算数组的交集

说明

array_intersect_assoc(array $array1,array $array2[,array $...]): array

array_intersect_assoc()返回一个数组，该数组包含了所有在$array1中也同时出现在所有其它参数数组中的值。注意和array_intersect()不同的是键名也用于比较。

参数

$array1: 要检查的主值。
$array2: 要比较的数组。; 要对比的数组变量的列表。

返回值

返回数组，该数组包含了所有在$array1中也同时出现在所有其它参数数组中的值。

范例

Example #1array_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);
?>

以上例程会输出：

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。

键值对key => value中的两个值仅在(string)$elem1 ===(string)$elem2时被认为相等。也就是说使用了严格检查，字符串的表达必须相同。

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

# 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
)

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.

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;
}
?>

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.