Remove duplicats from two multidimensional array

Question

I ran into a problem trying to get a unique array from two two multidimensional array, failed to do so.

I've tried search on solutions, but everything I can thing is only about one array.

Here are the two arrays.

Array
(
    [1] => Array
        (
            [title] => Strongest Links - Directory list
            [promotion] => At Strongest Links you can find good linking partners, track directory submission and manage your online promotion campaign. Try it for free.
            [domain] => http://www.strongestlinks.com
        )
)
Array
(
    [0] => Array
        (
            [title] => Strongest Links - Directory list
            [kbsize] => 88820
            [url] => http://www.strongestlinks.com/directories.php
            [meta_description] => At Strongest Links you can find good linking partners, track directory submission and manage your online promotion campaign. Try it for free.
            [kbsize_t] => 88.82kb
        )

    [3] => Array
        (
            [title] => 
Strongest Links - Directory list
            [kbsize] => 20303
            [url] => http://www.strongestlinks.com/directories/369
            [meta_description] => At Strongest Links you can find good linking partners, track directory submission and manage your online promotion campaign. Try it for free.
            [kbsize_t] => 20.303kb
        )

    [4] => Array
        (
            [title] => Strongest Links - Directory list
            [kbsize] => 20366
            [url] => http://www.strongestlinks.com/directories/317
            [meta_description] => At Strongest Links you can find good linking partners, track directory submission and manage your online promotion campaign. Try it for free.
            [kbsize_t] => 20.366kb
        )

    [5] => Array
        (
            [title] => SmartLinks.org - News, Reference, Facts - QuickLinks
            [kbsize] => 95526
            [url] => http://www.smartlinks.org
            [meta_description] => SmartLinks.org - QuickLinks/Favorites - News, Reference, Facts and Topics organized by Categories.
            [kbsize_t] => 95.526kb
        )

)

I'm trying to make a function which compare url field from array 1 with domain field from array 2, and returns array 1 minus elements which are also found in array 2.

And even better function would also be if it could compare the field url in array 1 with domain field in array 2, and return with how much the two fields are matching.

Answer 1

You want to do this:

1. make a lookup table where you can quickly check if a domain should be excluded in without having to search the entire array
2. make a function that takes a url and returns its domain
3. make a new array that inserts items that exist in array2 so long as those domains aren't in your lookup table of excluded domains.

Here's the code:

// the array of domains that we want to exclude
// you can still have your other properties too, I just
// excluded them to make the example cleaner :)
$array1 = [
    [ 'domain' => 'http://www.strongestlinks.com' ]  
];

// the array of urls
$array2 = [
    [ 'url' => 'http://www.strongestlinks.com/directories.php' ],
    [ 'url' => 'http://www.strongestlinks.com/directories/369' ],
    [ 'url' => 'http://www.smartlinks.org' ] 
];

// build a lookup table of domains that we want to subtract from array2
$blacklisted_domains = [];
foreach($array1 as $v) {
  $blacklisted_domains[$v['domain']] = true;
}

// small function to take a url and return its domain
function get_domain($url) {
  $parts = explode('/', $url);
  return $parts[0] . '//' . $parts[2];
}

// array3 will contain array2 - array1
$array3 = [];

// for each url in array2, find its domain and insert the
// url into array3 if the domain isnt in blacklisted_domains
foreach($array2 as $v) {
  $domain = get_domain($v['url']);
  if(!isset($blacklisted_domains[$domain])) {
    $array3[] = $v;
  }
}