PHP for loop will affect the page load speed?

$categories = array("google","adobe","microsoft","exoot","yahoo");
$sql='google,exoot,adobe';//from mysql_query
$categs = explode(",",$sql);

for($x=0;$x<count($categs);$x++){
    for($y=0;$y<count($categories);$y++){
        if($categs[$x] == $categories[$y]){
            $str .= $y.",";
        }
    }
}

echo str; // 0,3,1,

Will this code will affect page render time? Ca开发者_C百科n I do it using any other fast methods?

Thanks in advance.

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$str = implode(',', array_keys(array_intersect($categories, $categs)));

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You can use array_intersect() to find the common items and then use implode() to construct a comma-separated list:

Str = implode(',', array_intersect($categories, $categs)) . ',';

Unless you're dealing with a large number of items (thousands) it won't affect page speed. The one issue is that this intersection is O(n²). Putting the values into keys could speed it up considerably as that changes lookup time from O(n) to near O(1) making the whole operation O(n).

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yes it will since you are looping in a loop.

Best thing is to check with in array:

$categories = array("google","adobe","microsoft","exoot","yahoo");
$sql='google,exoot,adobe';//from mysql_query
$categs = explode(",",$sql);
$str = array();

foreach($categs as $id => $categs_check)
{
    if(in_array($categs_check, $categories))
    {
        //its better to put it into a array and explode it on a later point if you need it with comma.
        $str[] = $id;
    }
}

I'm not completely sure what you are trying to do but it should be something like the above

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I don't think that str_replace is a faster method than all the array functions but another possible solution is:

$categories = array("google","adobe","microsoft","exoot","yahoo");
$sql='google,exoot,adobe';//from mysql_query

foreach($categories as $i=> $c) {
     $sql = str_replace($c, $i, $sql);   
}

---

$arrCategories = array("google","adobe","microsoft","exoot","yahoo");
$sql='google,exoot,adobe';//from mysql_query
$arrCategs = explode(",",$sql);
$arrAns = array();

for($i = 0, $intCnt = count($arrCategs); $i <= $intCnt; $i++) {
    if(in_array($arrCategs[$i],$arrCategories)) {
        $arrAns[$arrCategs[$i]] = array_search($arrCategs[$i], $arrCategories);
    }
}

print "<pre>";
print_r($arrAns);
print "</pre>";