array_intersect_uassoc(): intersection between two arrays considering additional key checks through callback function

$new_array = array_intersect_uassoc ($array1, $array2,....,my_function());

Example with two arrays

function my_function($a, $b)
{
    if ($a === $b) {
        return 0;
    }
    return ($a > $b)? 1:-1;
}

$first=array('One' =>'First','Two'=>'Second','Three'=>'Third','Fourth');
$second=array('One'=> 'First','2nd'=>'Second','Three'=>'Third','Fourth');

$result=array_intersect_uassoc($first,$second,"my_function");
while (list ($key, $val) = each ($result)) {
echo "$key -> $val <br>";
}

One -> First 
Three -> Third 
0 -> Fourth 

Example: Comparing Arrays with Case-Insensitive Keys

$array1 = ["a" => "green", "B" => "red", "C" => "blue"];
$array2 = ["A" => "green", "b" => "yellow"];
$result = array_intersect_uassoc($array1, $array2, "strcasecmp");
print_r($result);  // Output: Array ( [a] => green )

Example: Custom Key Comparison Function

$array1 = ["apple" => 1, "banana" => 2];
$array2 = ["banana" => 2, "grape" => 3];
$result = array_intersect_uassoc($array1, $array2, function($key1, $key2) {
    return $key1 <=> $key2;  // Custom comparison
});
print_r($result);  // Output: Array ( [banana] => 2 )

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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