php - (Needle, Haystack) with 2 arrays, confused -

have been trying figure out simple problem 3 days , don't understand why function removes of values, leaves others in place.

this function checks list of bad domains against list of domains, if finds bad domain, removes domains list.

here's code:

// check each bad domain, against each array in array list  $bad_domains = array('youtube.com', 'facebook.com', 'google.com', 'twitter');  $good_domains = array( 'http://www.wufoo.com/', 'https://plus.google.com/u/0/b/105790754629987588694', 'http://studioduplateau.com/ss=', 'http://twitter.com/?lang=tic-toc', 'http://twitter.com/?lang=ka-boom', 'http://twitter.com/?lang=tic-toc', 'http://twitter.com/?lang=ka-boom', 'http://twitter.com/?lang=tic-toc', 'http://twitter.com/?lang=ka-boom', 'http://twitter.com/?lang=tic-toc', 'http://twitter.com/?lang=ka-boom', 'http://twitter.com/?lang=ka-boom', 'lastofthemohicans.com'     );  function remove_excluded_domains($good_domains, $bad_domains) {     for($x=0; $x<count($bad_domains); $x++)     {         for($y=0; $y<count($good_domains); $y++)          {             if(strpos($good_domains[$y], $bad_domains[$x]))             {             unset($good_domains[$y]);              $good_domains = array_values($good_domains);             }         }     }     return $good_domains; }  $spider_array = remove_excluded_domains($good_domains, $bad_domains); 

for reason returns:

[0] => http://www.wufoo.com/ [1] => http://studioduplateau.com/ss= [2] => http://twitter.com/?lang=ka-boom [3] => http://twitter.com/?lang=ka-boom [4] => http://twitter.com/?lang=ka-boom [5] => http://twitter.com/?lang=ka-boom [6] => lastofthemohicans.com 

so removes http://twitter.com/?lang=tic-toc, leaves http://twitter.com/?lang=ka-boom..

why that? tried play array_values, still doesn't work.

sorry silly array values, wanted stand out it's more clear. appreciate help.

use simple foreach loops, because way don't have use array_values() function. remove_excluded_domains() funciton should this:

function remove_excluded_domains($good_domains, $bad_domains) {     foreach($bad_domains $bad_domain){         foreach($good_domains $key => $good_domain){             if(strpos($good_domain, $bad_domain) !== false){                 unset($good_domains[$key]);              }         }     }     return $good_domains; }  $spider_array = remove_excluded_domains($good_domains, $bad_domains);  

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note: if want array indexed numerically use array_values() function on returned array, this:

$spider_array = array_values(remove_excluded_domains($good_domains, $bad_domains));