有关在URL中替换1个字符的更优雅解决方案的建议

Question

So, I have a URL I am receiving via an API. The pattern would be similar to https://www.example.co.uk/category/000000000k/0000

I want to replace the second k character, with a x char.

I tried using str_replace() but it also replaces the first k character.

So what I did was use preg_split() , so my solution is:

$url = preg_split( '/[\/]+/', 'https://www.example.co.uk/category/000000000k/0000' );
$url = $url[0] . '//' . $url[1] . '/' . $url[2] . '/' . str_replace( 'k', 'x', $url[3] ) . '/' . $url[4];

So, my solution works are long as the URL pattern does not change. However, I think it could be more elegant if my Regex was up to par.

Anyone here could point me to a better path?

Answer 1

If k/ always have numbers before that and another part doesn't have same pattern, this may work.

$url = "https://www.example.co.uk/category/000000000k/0000";
$url = preg_replace("/([0-9])k\//", "$1x/", $url);

Anoter pattern. Find 3rd / , make sub string, and replace.

$url = "https://www.example.co.uk/category/000000000k/0000";

$pos = 0;
for ($i = 0; $i < 3; $i++) {
    $pos = strpos($url, "/", $pos);
    if (FALSE === $pos) {
        // error
        break;
    }
    $pos++;
}

if ($pos) {
    $url_tmp = substr($url, $pos);
    $url_tmp = str_replace("k/", "x/", $url_tmp);
    $url = substr($url, 0, $pos).$url_tmp;
} else {
    // $pos is 0 or FALSE
    // error
}

If url source is not reliable, more checks may be needed.

Answer 2

$url = "https://www.example.co.uk/category/000000000k/0000";
echo preg_replace("/^[^k]+k[^k]+\Kk/", "x", $url),"\n";

Output:

https://www.example.co.uk/category/000000000x/0000

Explanation:

/               # regex delimiter
  ^             # beginning of line
    [^k]+       # 1 or more any character that is not k
    k           # 1rst letter k
    [^k]+       # 1 or more any character that is not k
    \K          # forget all we have seen until this position
    k           # 2nd letter k
/               # regex delimiter