PHP compares the key names and key values ​​of two arrays and returns the intersection function array_intersect_assoc()

Example

Compare the key names and key values ​​of two arrays and return the intersection:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"red","b"=>"green","c"=>"blue");

$result=array_intersect_assoc($a1,$a2);
print_r($result);
?>

Definition and usage

array_intersect_assoc() Function is used to compare the key names and key values ​​of two (or more) arrays and return the intersection.

This function compares the key names and key values ​​​​of two (or more) arrays, and returns an intersection array, which includes everything in the compared array (array1) and any other The key name and key value in the parameter array (array2 or array3, etc.).

Syntax

array_intersect_assoc(array1,array2,array3...)

Parameters	Description
array1	Required. The first array to compare with other arrays.
array2	Required. The array to compare to the first array.
array3,...	Optional. Additional array to compare with the first array.

Technical details

Return value:	Returns an intersection array, which contains All keys and values ​​in the array being compared (array1) and in any other parameter arrays (array2 or array3, etc.).
PHP version:	4.3.0+

更多实例

实例 1

比较三个数组的键名和键值，并返回交集：

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"red","b"=>"green","g"=>"blue");
$a3=array("a"=>"red","b"=>"green","g"=>"blue");

$result=array_intersect_assoc($a1,$a2,$a3);
print_r($result);
?>

实例

<?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。 

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