How to remove hostname from string using PHP?

Assuming you're working with a URL and not a long string containing a url...

$path = parse_url($url, PHP_URL_PATH);

You could use parse_url but then you would have to re-build the rest of the URL with different components:

$components = parse_url($url);
$result = $components['path'] . '?' .
          $components['query'] . '#' .
          $components['fragment'];

The following will simply return the Path of your URL:

<?php

$urls = array(
    'http://something.com/',
    'http://something.something.com/',
    'http://something.something.com/some/path',
    'http://something.something.com/some/path/?query=string',
    'http://something.something.com/some/path/?query=string#with-fragment',
);

foreach ($urls as $url) {
    var_dump(parse_url($url, PHP_URL_PATH));
}

#=> string(1) "/"
#=> string(1) "/"
#=> string(10) "/some/path"
#=> string(11) "/some/path/"
#=> string(11) "/some/path/"

Note, if you're just looking to strip the URL Scheme and the Host off the URL, and you want to keep the Query and the Fragment, you can use this:

foreach ($urls as $url) {
    $url = parse_url($url);
    $ret = $url['path'];
    if ($url['query']) $ret .= "?{$url[query]}";
    if ($url['fragment']) $ret .= "#{$url[fragment]}";
    var_dump($ret);
}

#=> string(1) "/"
#=> string(1) "/"
#=> string(10) "/some/path"
#=> string(24) "/some/path/?query=string"
#=> string(38) "/some/path/?query=string#with-fragment"

Better yet, If you're using the PECL HTTP Extension, you can use the http_build_url() method:

foreach ($urls as $url) {
    $url = http_build_url(array_key_intersect(
        parse_url($url),
        array_flip(array('path', 'query', 'fragment'))
    ));
    var_dump($url);
}

#=> string(1) "/"
#=> string(1) "/"
#=> string(10) "/some/path"
#=> string(24) "/some/path/?query=string"
#=> string(38) "/some/path/?query=string#with-fragment"

$url = "http://php.net/manual/en/function.parse-url.php?arg=value#anchor";

print_r(parse_url($url));

echo parse_url($url, PHP_URL_PATH);

The above example will output:

Array
(
    [scheme] => http
    [host] => php.net
    [path] => /manual/en/function.parse-url.php
    [query] => arg=value
    [fragment] => anchor
)

please refer to parse-url

Specify one of PHP_URL_SCHEME, PHP_URL_HOST, PHP_URL_PORT, PHP_URL_USER, PHP_URL_PASS, PHP_URL_PATH, PHP_URL_QUERY or PHP_URL_FRAGMENT to retrieve just a specific URL component as a string (except when PHP_URL_PORT is given, in which case the return value will be an integer).

What you want appears to be the $_SERVER['REQUEST_URI']. Or you can get that with parse_url()

Or if you insist on using regex, [EDIT] don't.

$url = "www.domain.com/sds?test=1&test2=2&test3=3";
$query = parse_url($url, PHP_URL_QUERY);
parse_str($query, $query_array);

Doesn't matter what before "?". Will output

array {
 'test' => string '1' (length=1)
 'test2' => string '2' (length=1)
 'test3' => string '3' (length=1)
}

You can get it from the first /, // not included.

$url = "https://www.facebook.com/hhhhhh?2342";
$pos = strpos($url,"://");
$pos = false === $pos ? 0 : $pos + 3;
echo substr($url,strpos($url,'/',$pos));