PHP - Replacing characters with stars, except when there is a minus - php

Question

How can I replace a string with stars except the first and the last letter but not a minus in case there is one.
Here for better illustration what I try to get:
From:
url-name
To
u**-***e
This is what I have so far:
function get_starred($str) {
$len = strlen($str);
return substr($str, 0, 1).str_repeat('_', $len - 2).substr($str, $len - 1, 1);
}

Answer 1

You could use the PCRE verbs to skip the first character of a string, last character of a string, and any -s. Like this:
(^.|-|.$)(*SKIP)(*FAIL)|.
https://regex101.com/r/YfrZ8r/1/
PHP example using preg_replace
preg_replace('/(^.|-|.$)(*SKIP)(*FAIL)|./', '*', 'url-name');
https://3v4l.org/0dSPQ

Answer 2

hey try implmenting the following:
function get_starred($str) {
$str_array =str_split($str);
foreach($str_array as $key => $char) {
if($key == 0 || $key == count($str_array)-1) continue;
if($char != '-') $str[$key] = '*';
}
return $str;
}

Answer 3

user3783242 has a great solution - However, if you for some reason do not want to use preg_replace(), you could do the following:
function get_starred($str) {
//make the string an array of letters
$str = str_split($str);
//grab the first letter (This also removes the first letter from the array)
$first = array_shift($str);
//grab the last letter (This also removes the last letter from the array)
$last = array_pop($str);
//loop through leftover letters, replace anything not a dash
//note the `&` sign, this is called a Reference, it means that if the variable is changed in the loop, it will be changed in the original array as well.
foreach($str as &$letter) {
//if letter is not a dash, set it to an astrisk.
if($letter != "-") $letter = "*";
}
//return first letter, followed by an implode of characters, followed by the last letter.
return $first . implode('', $str) . $last;
}

Answer 4

Here is mine:
$string = 'url-name foobar';
function star_replace($string){
return preg_replace_callback('/[-\w]+/i', function($match){
$arr = str_split($match[0]);
$len = count($arr)-1;
for($i=1;$i<$len;$i++) $arr[$i] = $arr[$i] == '-' ? '-' : '*';
return implode($arr);
}, $string);
}
echo star_replace($string);
This works on multiple words.
Output
u**-***e f****r
Sandbox
And it also takes into account puctuation
$string = 'url-name foobar.';
Output
u**-***e f****r.