//strip the "http://" part. Note: Doesn t work for HTTPS!
$url = substr("http://www.example.com/elderly-care-advocacy/mental-capacity-act-advance-medical-directive.html", 7);

// split the URL in parts
$parts = explode("/", $url);

// The second part (offset 1) is the part we look for
if (count($parts) > 1) {
    $segment = $parts[1];
} else {
    throw new Exception("Full URLs please!");
}

$url = "http://www.example.co.uk/elderly-care-advocacy/mental-capacity-act-advance-medical-directive.html";
$parts = parse_url($url);
$host = $parts[ host ];
$path = $parts[ path ];

$items = preg_split( /// ,$path,null,PREG_SPLIT_NO_EMPTY);

$firstPart = $items[0];

off the top of my head:

$url = http://www.example.co.uk/elderly-care-advocacy/mental-capacity-act-advance-medical-directive.html
$urlParts = parse_url($url); // An array
$target_string = $urlParts[1] //  elderly-care-advocacy 

Cheers

explode( / , $a);

All you should do, is parse url first, and then explode string and get first part. With some sanity checks that would lok like following:

$url =  http://www.?.co.uk/elderly-care-advocacy/mental-capacity-act-advance-medical-directive.html ;
$url_parts = parse_url($url);
if (isset($url_parts[ path ])) {
    $path_components = explode( / , $ul_parts[ path ]);
    if (count($path_components) > 1) {
        // All is OK. Path s first component is in $path_components[0]
    } else {
        // Throw an error, since there is no directory specified in path
        // Or you could assume, that $path_components[0] is the actual path
    }
} else {
    // Throw an error, since there is no path component was found
}

I was surprised too, but this works.

$url= http://www.?.co.uk/elderly-care-advocacy/... 
$result=explode( / ,$url)[3];

I think a Regular Expression should be fine for that.

Try using e.g.: /[^/]+/ that should give you /elderly-care-advocacy/ as the second index of an array in your example.

(The first string is /www.?.com/)

Parse_URL is your best option. It breaks the URL string down into components, which you can selectively query.

This function could be used:

function extract_domain($url){

    if ($url_parts = parse_url($url), $prefix =  www. , $suffix =  .co.uk ) {
        $host = $url_parts[ host ];
        $host = str_replace($prefix,  ,$host);
        $host = str_replace($suffix,  ,$host);
        return $host;
    }
    return false;
}

$host_component = extract_domain($_SERVER[ REQUEST_URI ]);