PHP Filter Array for double Elements -

i've got question. got array filled external links like:

www.google.de www.google.com/test 

and on. no array filltered. if there links in array this:

www.google.de www.google.de/test www.google.de/fuuuu 

i want www.google.de link , filter rest out of it. startet use array_diff_key not working should. here snippet.

$d_array = array_diff_key($externalarray, array_unique($externalarray)); 

thanks help. greats, traxstar

finally, did :

$arr = [     'www.google.de',     'http://www.google.de/test',     'www.google.de/fufufufu',     'www.google.com/cctvvmb',     'https://www.google.com/',     'google.co.uk/hello', ];   // based on http://stackoverflow.com/questions/1201194/php-getting-domain-name-from-subdomain function get_domain($url) {     if(preg_match('/(?p<domain>[a-z0-9][a-z0-9\-]{1,63}\.[a-z\.]{2,6})$/i', $url, $regs))     {         return $regs['domain'];     }      return false; }  function get_duplicated_domains($arr) {     $domains = [];      // looping array, processing of     foreach($arr $url)     {         // lower text         $url = strtolower($url);          // removing eventual http & https         $url = str_replace('http://', '', $url);         $url = str_replace('https://', '', $url);          // replacing string before first slash         $url = explode('/', $url);          // extracting top level domain         $url = get_domain($url[0]);          // registering domain in $domains array or incrementing         if(array_key_exists($url, $domains))         {             $domains[$url]++;         }         else         {             $domains[$url] = 0;         }     }      // gathering data     return array_keys(array_filter($domains)); }  $res = get_duplicated_domains($arr); 

result :

array (     [0] => google.de     [1] => google.com ) 

what script doing ?

1 - looping array

• 1.1 - lowering url string prevent http mismatch http exemple

• 1.2 - removing http:// & https:// strings, make same format

• 1.3 - extracting top level domain name

• 1.4 - registering or incrementing $domains array on extracted top level domain name

2 - filtering array (0, null, false, empty strings, removed, that's why register domain name 0 , not 1) keep 'doubt' domains (the ones present more 1 time in array)

3 - getting keys of array (because keys domain names)

btw i'm running php 5.6.2