PHP array introductory tutorial: Intersection of associative arrays

The PHP function array_intersect_assoc() is basically the same as array_intersect(), except that it also considers the keys of the array in the comparison. Therefore, only key/value pairs that appear in the first array and also appear in all other input arrays are returned in the result array.

The form is as follows: array array_intersect_assoc(array array1,array array2[,arrayN…])

Example, return all key/value pairs that appear in the $fruit1 array and also appear in $fruit2 and $fruit3:

<?php
//求关联数组的交集
$fruit1 = array("red"=>"Apple","yellow"=>"Banana","orange"=>"Orange");  
$fruit2 = array("yellow"=>"Pear","red"=>"Apple","purple"=>"Grape");  
$fruit3 = array("green"=>"Watermelon","orange"=>"Orange","red"=>"Apple");  
$intersection = array_intersect_assoc($fruit1, $fruit2, $fruit3);  
print_r($intersection); //by bbs.it-home.org

// output  
// Array ( [red] => Apple )  
?>