PHP - 将代码应用于子页面

Question

I have this code:

<?php $url = JURI::getInstance()->toString();
if ($url == "http://example.com/news/latest/"){
  echo "This is latest page";
} else {
  echo "This is not latest page";
}
?>

What I'm trying to do is instead of 'http://example.com/news/latest/', how can I select the pages/items under /latest/. If it makes any more sense, here's a syntax:

if ($url == "http://example.com/news/latest/" + ANYTHING UNDER THIS)

I cannot use not equal to ($url !=) since it will include other parent pages not equal to /latest/. I just want what's under it. If anyone understands it, I need help on how to put it into code.

Update: What I'm trying to do is if the page is example.com/news/latest, it will echo "Latest". And if for example, I am in example.com/news/latest/subpage1/subpage2, it will echo "You are in a page that is under Latest." Anything beyond "Latest" will echo that.

Answer 1

$str = 'example.com/news/latest/dfg';

preg_match('/example.com\/news\/([^\/]+)\/?(.*)/', $str, $page);

if(isset($page[2]) && $page[2])
    echo 'You are under: ' , $page[1];
elseif(isset($page[1]))
    echo 'At: ' , $page[1];
else
    echo 'Error';

Edit: after clarification switched to regular expression.