How to make a PHP regular expression to remove certain text?

Question

PHP

I create a command to get the user's ID from a link on the page, there are three cases:
1. https://vk.com/none
2. https://vk.com/id123
3. @none
In the first case, the regular expression should leave only none.
In the second, everything is the same as in the first, cut to id123.
In the third case, nothing should be deleted.

Answer 1

Replacing via str_replace is enough

$newStr = str_replace('https://vk.com/', '', $str);

Answer 2

<?php
$a = 'https://vk.com/none';
$b = 'https://vk.com/id123';
$c = 'https://vk.com/id123456?a=b';
$d = '@none';
$e = 'some text';

function getUserId($link)
{
    if (preg_match('/vk.com\/(?<id>[\w\d]+)/ui', $link, $m) && !empty($m['id'])) return $m['id'];
    if (preg_match('/(?<uid>@[\w\d]+)/ui', $link, $m) && !empty($m['uid'])) return $m['uid'];
    return false;
}

var_dump(getUserId($a));
var_dump(getUserId($b));
var_dump(getUserId($c));
var_dump(getUserId($d));
var_dump(getUserId($e));

//string(4) "none"
//string(5) "id123"
//string(8) "id123456"
//string(5) "@none"
//bool(false)

Answer 3

$string = 'https://vk.com/none';

function find(string $str) {
    $result = '';
    if (preg_match('/^https:\/\/vk.com\//', $str)) {
        $result = substr($str, 15);
    } else {
        $result = $str;
    }

    return $result;
}