Strpos（）返回意外的字符串

Question

I for the life of me cannot figure out why this is not working.

$value="http://www.google.com/trends/hottrends/atom/feed?pn=p1";

$startvar="http://";
$endvar="/";

$start = strpos($value,$startvar);

$end = strpos($value,$endvar,$start) + 8;

$results = substr($value,$start,$end-$start);
echo $results;

No matter what I do it will always return the http:// which I do not want. I just want the www.google.com. I'm using this in another area and there it's behaving exactly like I want. I did get this to work if I use a numerical starting point and not $startvar but that won't necessarily work all the time.

I'm sure it's something simple that I'm missing.

Thanks Bruce

Answer 1

You need to skip over the whole $startvar token to get to the next bit of your string. strpos returns the beginning of the match.

$start = strpos($value,$startvar) + strlen($startvar);

Although you will also need to make sure that strpos hasn't returned false , which it will do if $startvar is not found:

$pos = strpos($value, $startvar)
if ($pos !== false)
{
   $start = $pos + strlen($startvar)
   //... other steps here...
}

If your objective is simply to parse a URL, you can use the PHP function parse_url , which will make your life much easier.

Answer 2

Why not use

$value="http://www.google.com/trends/hottrends/atom/feed?pn=p1";
list($a,$b,$c) = split('[/]',$value);

echo'<br/>a = ',$a;
echo'<br/>b = ',$b;
echo'<br/>c = ',$c;

You will find that $c is your answer.