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

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